Introduction to Computer Science - Exercise 3

Name: Saggi Mizrahi • ID: 032493124 • Group: מעוף א' • Date: November 5, 2013

Conditionals

1.

Code:

/* diet.cpp
 * This program recommends vague diet menus according to age, weight and
 * height.
 *
 * Saggi Mizrahi 05 November 2013
 */
#include <iostream>

using namespace std;

/* Calculate optimal diet according to age, weight and height
 * Input: age, weight and height.
 * Output: the recommended diet for your age and height to weight ratio.
 */
int main()
{
    // declaration of constants
    const char DIET_OPTION_A = 'A';
    const char DIET_OPTION_B = 'B';
    const char DIET_OPTION_C = 'C';
    const char DIET_OPTION_NONE = 'N';

    // declaration of variables
    // All variables are set to -1 to help detect algorithmic errors.
    int age = -1;
    double weight = -1;
    int height = -1;
    double ratio = -1;
    char optimal_diet = DIET_OPTION_NONE;

    // getting input from the user
    cout << "please enter your age (in years): ";
    cin >> age;

    cout << "please enter your weight (in KG): ";
    cin >> weight;

    cout << "please enter your height (in centimeters): ";
    cin >> height;

    // compute ratio
    if (weight != 0) {
        ratio = height / weight;
    }

    // find appropriate diet

    // first check if we are in the correct ranges
    if (age < 11 or age > 120 or ratio < 0.5 or ratio > 5) {
        optimal_diet = DIET_OPTION_NONE;
    } else if (ratio < 2) {
        optimal_diet = DIET_OPTION_A;
    } else if (ratio < 3.5) {
        if (age <= 40) {
            optimal_diet = DIET_OPTION_B;
        } else {
            optimal_diet = DIET_OPTION_C;
        }
    } else if (age >= 21 and age <= 40) {
        optimal_diet = DIET_OPTION_A;
    } else {
        optimal_diet = DIET_OPTION_C;
    }

    // outputting the result
    if (optimal_diet == DIET_OPTION_NONE) {
        cout << "no suitable diet found" << endl;
    } else {
        cout << "the best diet option for you is option " <<
            optimal_diet << endl;
    }
}

Outputs:

Check given example:

please enter your age (in years): 18
please enter your weight (in KG): 60
please enter your height (in centimeters): 180
the best diet option for you is option B

Check weight is 0:

please enter your age (in years): 18
please enter your weight (in KG): 0
please enter your height (in centimeters): 180
no suitable diet found

Check too young:

please enter your age (in years): 10
please enter your weight (in KG): 60
please enter your height (in centimeters): 180
no suitable diet found

Check too old:

please enter your age (in years): 121
please enter your weight (in KG): 60
please enter your height (in centimeters): 180
no suitable diet found

check ration between 0.5 and 2:

please enter your age (in years): 50
please enter your weight (in KG): 60
please enter your height (in centimeters): 60
the best diet option for you is option A

check ratio to low:

please enter your age (in years): 50
please enter your weight (in KG): 60
please enter your height (in centimeters): 10
no suitable diet found

2.

Code:

/* order.cpp
 * This program receives 3 numbers and prints them out in descending order.
 *
 * Saggi Mizrahi 05 November 2013
 */
#include <iostream>

using namespace std;

/* Order 3 numbers in descending order.
 * Input: 3 numbers.
 * Output: The numbers printed out in descending order.
 */
int main()
{
    // declaration of variables
    int num1;
    int num2;
    int num3;

    int tmp;

    // getting input from the user
    cout << "please enter 3 numbers: ";
    cin >> num1 >> num2 >> num3;

    // order numbers
    if (num3 > num2) {
        tmp = num3;
        num3 = num2;
        num2 = tmp;
    }

    if (num2 > num1) {
        tmp = num2;
        num2 = num1;
        num1 = tmp;
    }

    if (num3 > num2) {
        tmp = num3;
        num3 = num2;
        num2 = tmp;
    }

    // outputting the result
    cout << num1 << " " << num2 << " " << num3 << endl;
}

Outputs:

please enter 3 numbers: 1 2 3
3 2 1

please enter 3 numbers: 1 3 2
3 2 1

please enter 3 numbers: 3 2 1
3 2 1

please enter 3 numbers: 2 3 1
3 2 1

please enter 3 numbers: 1 3 2
3 2 1

please enter 3 numbers: 2 1 3
3 2 1

please enter 3 numbers: 3 1 2
3 2 1

3.

Code

/* drivetime.cpp
 * Program that calculates the arrivale time given the start time and duration
 * in seconds
 *
 * Saggi Mizrahi 5 November 2013
 */

#include <iostream>

using namespace std;

/* Input: 4 integers representing hours, minutes, seconds and duration in
 *        seconds.
 * Output: The arrival time.
 */
int main() {
    // declaration of constants
    const int SECONDS_IN_MINUTE = 60;
    const int MINUTES_IN_HOUR = 60;
    const int HOURS_IN_DAY = 24;

    // declaration of variables
    int hours;
    int minutes;
    int seconds;
    int duration;

    bool inputValid = true;

    // getting input from the user
    cout << "please enter the starting time (H M S) " <<
        "followed by drive duration in seconds: ";
    cin >> hours >> minutes >> seconds >> duration;

    // validate input
    if (seconds < 0 || seconds > 59) {
        cout << "Invalid number of seconds: " << seconds <<
            ". number must be between 0 and 59" << endl;
        inputValid = false;
    }

    if (minutes < 0 || minutes > 59) {
        cout << "Invalid number of minutes: " << minutes <<
            ". number must be between 0 and 59" << endl;
        inputValid = false;
    }

    if (hours < 0 || hours > 23) {
        cout << "Invalid number of hours: " << hours <<
            ". number must be between 0 and 23" << endl;
        inputValid = false;
    }

    if (!inputValid) {
        // Input is ivalid, bail out
        return 1;
    }

    // caluculating the end time
    seconds += duration;

    minutes += seconds / SECONDS_IN_MINUTE;
    seconds %= SECONDS_IN_MINUTE;

    hours += minutes / MINUTES_IN_HOUR;
    minutes %= MINUTES_IN_HOUR;

    hours %= HOURS_IN_DAY;

    // outputting the result
    cout << hours << " " << minutes << " " << seconds << endl;

    return 0;
}

Outputs

Input from assignment:

please enter the starting time (H M S) followed by drive duration in seconds: 12 31 10 4004
13 37 54

Totally wrong input:

please enter the starting time (H M S) followed by drive duration in seconds:  -1 -1 -1 4004
Invalid number of seconds: -1. number must be between 0 and 59
Invalid number of minutes: -1. number must be between 0 and 59
Invalid number of hours: -1. number must be between 0 and 23

There never seem to be enough hours in a day:

please enter the starting time (H M S) followed by drive duration in seconds: 25 10 14 4
Invalid number of hours: 25. number must be between 0 and 23

4.

Code

/* round.cpp
 * Program that rounds numbers with various algorithms
 *
 * Saggi Mizrahi 5 November 2013
 */

#include <iostream>

using namespace std;

/* Input: An algorithm of choice and a real number
 * Output: The number rounded according to the selected algorithm.
 */
int main() {
    // declaration of constants
    const int ROUND_DOWN = 1;
    const int ROUND_UP = 2;
    const int ROUND = 3;

    // declaration of variables
    double num = 0;
    int roundAlgorithm = -1;
    int result = 0;

    // select the algorithm
    cout << "available algorithms" << endl;
    cout << "\t1.Floor round" << endl;
    cout << "\t2.Ceiling round" << endl;
    cout << "\t3.Round to the nearest whole number" << endl;
    cout << "please choose a round algorithm: ";

    cin >> roundAlgorithm;

    // get the number
    cout << "please enter a number you wish to round: ";
    cin >> num;

    // round number
    switch (roundAlgorithm) {
    case ROUND_DOWN:
        result = num;
        break;
    case ROUND_UP:
        result = num;
        if (num > result) {
            result++;
        }
        break;
    case ROUND:
        result = num + 0.5;
        break;
    }

    // outputting the result
    cout << result << endl;

    return 0;
}

Outputs

available algorithms
    1.Floor round
    2.Ceiling round
    3.Round to the nearest whole number
please choose a round algorithm: 1
please enter a number you wish to round: 0.5
0

available algorithms
    1.Floor round
    2.Ceiling round
    3.Round to the nearest whole number
please choose a round algorithm: 2
please enter a number you wish to round: 0.5
1

available algorithms
    1.Floor round
    2.Ceiling round
    3.Round to the nearest whole number
please choose a round algorithm: 3
please enter a number you wish to round: 0.5
1

available algorithms
    1.Floor round
    2.Ceiling round
    3.Round to the nearest whole number
please choose a round algorithm: 3
please enter a number you wish to round: 0.9
1

available algorithms
    1.Floor round
    2.Ceiling round
    3.Round to the nearest whole number
please choose a round algorithm: 3
please enter a number you wish to round: 0.4
0

available algorithms
    1.Floor round
    2.Ceiling round
    3.Round to the nearest whole number
please choose a round algorithm: 2
please enter a number you wish to round: 0.9999999
1

available algorithms
    1.Floor round
    2.Ceiling round
    3.Round to the nearest whole number
please choose a round algorithm: 2
please enter a number you wish to round: 0.0000000001
1

Loops

1א.

Code:

/* stars.cpp
 * This program prints out a lovely asterisk formation
 *
 * Saggi Mizrahi 05 November 2013
 */
#include <iostream>

using namespace std;

/* This program prints out a asterisk formation as two right triangles touching
 * each other.
 * Input: number of lines.
 * Output: The said formation.
 */
int main()
{
    // declaration of constants
    const char ASTERISK = '*';
    const char SPACE = ' ';

    // declaration of variables
    int n;
    int totalWidth;

    // getting input from the user
    cout << "please enter a number: ";
    cin >> n;

    // draw shape
    totalWidth = n * 2;
    for (int line = 0; line < n; line++) {
        for (int i = 0; i < totalWidth; i++) {
            if (i <= line || i >= totalWidth - line - 1) {
                cout << ASTERISK;
            } else {
                cout << SPACE;
            }
        }
        cout << endl;
    }

    return 0;
}

Schema:

for (...;...;...) // Loop that goes line by line
{
    for (...;...;...) // Loop that prints spaces and asterixes
    {
    }
    // New line
}

Outputs:

Check given example:

please enter a number: 5
*        *
**      **
***    ***
****  ****
**********

1ב.

Code:

/* pyramid.cpp
 * This program prints out a letter pyramid
 *
 * Saggi Mizrahi 05 November 2013
 */
#include <iostream>

using namespace std;

/* This program prints out a letter pyramid
 * each other.
 * Input: the central brick in the letter pyramid.
 * Output: The letter pyramid.
 */
int main()
{
    // declaration of constants
    const char START_CHAR = 'a';

    // declaration of variables
    char endChar;
    int numLines;
    int numSpaces;

    // getting input from the user
    cout << "please enter a char: ";
    cin >> endChar;

    // draw shape
    numLines = endChar - START_CHAR + 1;
    for (int i = 0; i < numLines; i++) {
        numSpaces = numLines - i - 1;
        for (int j = 0; j < numSpaces; j++) {
            cout << " ";
        }

        for (int j = 0; j < i; j++) {
            cout << char(START_CHAR + j);
        }

        for (int j = i; j >= 0; j--) {
            cout << char(START_CHAR + j);
        }
        cout << endl;
    }

    return 0;
}

Schema:

for (...;...;...) // Loop that goes line by line
{
    for (...;...;...) // Loop that prints spaces
    {
    }
    for (...;...;...) // Loop that prints letters in ascending order
    {
    }
    for (...;...;...) // Loop that prints letter in descending order
    {
    }
    // New line
}

Outputs:

Check given example:

please enter a char: d
   a
  aba
 abcba
abcdcba

1ג.

Code:

/* shtrudelville.cpp
 * This program prints out a number formation
 *
 * Saggi Mizrahi 05 November 2013
 */
#include <iostream>

using namespace std;

/* This program prints out a number formation
 *
 * Input: two numbers.
 * Output: The requested formation.
 */
int main()
{
    // declaration of constants
    const char SEPERATOR = '@';

    // declaration of variables
    int n;
    int k;

    // getting input from the user
    cout << "please enter 2 numbers: ";
    cin >> n >> k;

    // draw shape
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < k; j++) {
            for (int s = 0; s < n; s++) {
                cout << (s + i) % n;
            }
            cout << SEPERATOR;
        }
        cout << endl;
    }

    return 0;
}

Schema:

for (...;...;...) // Loop that goes line by line
{
    for (...;...;...) // Loop goes section by section
    {
        for (...;...;...) // Loop that prints the numbers in each section
        {
        }
        // Seperator
    }
    // New line
}

Outputs:

Check given example:

please enter 2 numbers: 5 3
01234@01234@01234@
12340@12340@12340@
23401@23401@23401@
34012@34012@34012@
40123@40123@40123@

1ד.

Code:

/* hashcash.cpp
 * This program prints out a $# formation
 *
 * Saggi Mizrahi 05 November 2013
 */
#include <iostream>

using namespace std;

/* This program prints out a $# formation
 *
 * Input: two numbers.
 * Output: The requested formation.
 */
int main()
{
    // declaration of constants
    const char SEPERATOR = '@';

    const char CHAR_A = '$';
    const char CHAR_B = '#';

    // declaration of variables
    int n;
    int k;
    char startChar = CHAR_A;
    char endChar = CHAR_B;

    // getting input from the user
    cout << "please enter 2 numbers: ";
    cin >> n >> k;

    // draw shape
    for (int i = 1; i <= n; i++) {
        for (int j = 0; j < k; j++) {
            for (int s = 0; s < n; s++) {
                if (s < i) {
                    cout << startChar;
                } else {
                    cout << endChar;
                }
            }
            cout << SEPERATOR;
        }
        cout << endl;

        // Flip chars
        startChar = startChar == CHAR_A ? CHAR_B : CHAR_A;
        endChar = endChar == CHAR_A ? CHAR_B : CHAR_A;
    }

    return 0;
}

Schema:

for (...;...;...) // Loop that goes line by line
{
    for (...;...;...) // Loop goes section by section
    {
        for (...;...;...) // Loop that prints the symbols
        {
        }
        // Seperator
    }
    // New line
}

Outputs:

Check given example:

please enter 2 numbers: 5 3
$####@$####@$####@
##$$$@##$$$@##$$$@
$$$##@$$$##@$$$##@
####$@####$@####$@
$$$$$@$$$$$@$$$$$@

2א.

Code:

/* averages.cpp
 * This program takes numbers and prints out the algebraical and geometrical averages.
 *
 * Saggi Mizrahi 05 November 2013
 */
#include <iostream>
#include <math.h>

using namespace std;

/* This program takes numbers and prints out the algebraical and geometrical averages.
 *
 * Input: 10 numbers.
 * Output: The algebraical and geometrical (when possible) averages.
 */
int main()
{
    // declaration of constants
    const int NUM_ENTRIES = 10;

    // declaration of variables
    int positiveEntriesNum = 0;
    int num;
    int sum = 0;
    int mul = 1;

    // getting input from the user
    for (int i = 0; i < NUM_ENTRIES; i++) {
        cout << "please enter a number: ";
        cin >> num;
        sum += num;
        if (num > 0) {
            positiveEntriesNum++;
            mul *= num;
        }
    }

    if (positiveEntriesNum == 0) {
        cout << "No positive numbers entered, no geometrical" <<
            " average is possible." << endl;
    } else {
        cout << "Geometric average is: " <<
            pow(mul, 1./positiveEntriesNum) << endl;
    }

    cout << "Algebraic average is: " << sum / double(NUM_ENTRIES) << endl;

    return 0;
}

Outputs:

please enter a number: 1
please enter a number: 2
please enter a number: 3
please enter a number: 4
please enter a number: 5
please enter a number: 6
please enter a number: 7
please enter a number: 8
please enter a number: 9
please enter a number: 0
Geometric average is: 4.14717
Algebraic average is: 4.5

please enter a number: 0
please enter a number: 0
please enter a number: 0
please enter a number: 0
please enter a number: 3
please enter a number: 3
please enter a number: 0
please enter a number: 0
please enter a number: 0
please enter a number: 0
Geometric average is: 3
Algebraic average is: 0.6

please enter a number: 0
please enter a number: 0
please enter a number: 0
please enter a number: 0
please enter a number: 0
please enter a number: 0
please enter a number: 0
please enter a number: 0
please enter a number: 0
please enter a number: 0
No positive numbers entered, no geometrical average is possible.
Algebraic average is: 0

2ב.

Code:

/* averages.cpp
 * This program takes numbers and prints out the algebraical and geometrical averages.
 *
 * Saggi Mizrahi 05 November 2013
 */
#include <iostream>
#include <math.h>

using namespace std;

/* This program takes numbers and prints out the algebraical and geometrical averages.
 *
 * Input: The amount of numbers to read and then that amount of numbers.
 * Output: The algebraical and geometrical (when possible) averages.
 */
int main()
{
    // declaration of constants

    // declaration of variables
    int numEntries = 10;
    int positiveEntriesNum = 0;
    int num;
    int sum = 0;
    int mul = 1;

    cout << "please enter number of entries: ";
    cin >> numEntries;

    // getting input from the user
    for (int i = 0; i < numEntries; i++) {
        cout << "please enter a number: ";
        cin >> num;
        sum += num;
        if (num > 0) {
            positiveEntriesNum++;
            mul *= num;
        }
    }

    if (positiveEntriesNum == 0) {
        cout << "No positive numbers entered, no geometrical" <<
            " average is possible." << endl;
    } else {
        cout << "Geometric average is: " <<
            pow(mul, 1./positiveEntriesNum) << endl;
    }

    if (numEntries == 0) {
        cout << "No numbers entered, no algebraic" <<
            " average is possible." << endl;
    } else {
        cout << "Algebraic average is: " << sum / double(numEntries) <<
            endl;
    }

    return 0;
}

Outputs:

please enter number of entries: 10
please enter a number: 1
please enter a number: 2
please enter a number: 3
please enter a number: 4
please enter a number: 5
please enter a number: 6
please enter a number: 7
please enter a number: 8
please enter a number: 9
please enter a number: 0
Geometric average is: 4.14717
Algebraic average is: 4.5

please enter number of entries: 10
please enter a number: 0
please enter a number: 0
please enter a number: 0
please enter a number: 0
please enter a number: 3
please enter a number: 3
please enter a number: 0
please enter a number: 0
please enter a number: 0
please enter a number: 0
Geometric average is: 3
Algebraic average is: 0.6

please enter number of entries: 10
please enter a number: 0
please enter a number: 0
please enter a number: 0
please enter a number: 0
please enter a number: 0
please enter a number: 0
please enter a number: 0
please enter a number: 0
please enter a number: 0
please enter a number: 0
No positive numbers entered, no geometrical average is possible.
Algebraic average is: 0

please enter number of entries: 0
No positive numbers entered, no geometrical average is possible.
No numbers entered, no algebraic average is possible.

2ג.

Code:

/* averages.cpp
 * This program takes numbers and prints out the algebraical and geometrical averages.
 *
 * Saggi Mizrahi 05 November 2013
 */
#include <iostream>
#include <math.h>

using namespace std;

/* This program takes numbers and prints out the algebraical and geometrical averages.
 *
 * Input: N numbers terminated with -1.
 * Output: The algebraical and geometrical (when possible) averages.
 */
int main()
{
    // declaration of constants

    // declaration of variables
    int numEntries = 0;
    int positiveEntriesNum = 0;
    int num = 0;
    int sum = 0;
    int mul = 1;

    // getting input from the user
    while(num >= 0) {
        cout << "please enter a number: ";
        cin >> num;
        if (num >= 0) {
            numEntries++;
            sum += num;
            if (num > 0) {
                positiveEntriesNum++;
                mul *= num;
            }
        }
    }

    if (positiveEntriesNum == 0) {
        cout << "No positive numbers entered, no geometrical" <<
            " average is possible." << endl;
    } else {
        cout << "Geometric average is: " <<
            pow(mul, 1./positiveEntriesNum) << endl;
    }

    if (numEntries == 0) {
        cout << "No numbers entered, no algebraic" <<
            " average is possible." << endl;
    } else {
        cout << "Algebraic average is: " << sum / double(numEntries) <<
            endl;
    }

    return 0;
}

Outputs:

please enter a number: 1
please enter a number: 2
please enter a number: 3
please enter a number: 4
please enter a number: 5
please enter a number: 6
please enter a number: 7
please enter a number: 8
please enter a number: 9
please enter a number: 0
please enter a number:  -1
Geometric average is: 4.14717
Algebraic average is: 4.5

please enter a number: 0
please enter a number: 0
please enter a number: 0
please enter a number: 0
please enter a number: 3
please enter a number: 3
please enter a number: 0
please enter a number: 0
please enter a number: 0
please enter a number: 0
please enter a number:  -1
Geometric average is: 3
Algebraic average is: 0.6

please enter a number: 0
please enter a number: 0
please enter a number: 0
please enter a number: 0
please enter a number: 0
please enter a number: 0
please enter a number: 0
please enter a number: 0
please enter a number: 0
please enter a number: 0
please enter a number:  -1
No positive numbers entered, no geometrical average is possible.
Algebraic average is: 0

please enter a number:  -1
No positive numbers entered, no geometrical average is possible.
No numbers entered, no algebraic average is possible.

3.

Code

/* decoct.cpp
 * Program that prints out the decimal value of an octal number
 *
 * Saggi Mizrahi 5 November 2013
 */

#include <iostream>

using namespace std;

/* Input: An octal number.
 * Output: The decimal representation of the input octal value.
 */
int main() {
    // declaration of variables
    char c = '\0';
    int value = 0;

    // collect input and build result
    cout << "please enter an octal number: ";
    c = cin.get();
    while (c != '\n') {
        value = (value * 8) + (c - 48);
        c = cin.get();
    }

    // output result
    cout << value << endl;

    return 0;
}

Outputs

please enter an octal number: 375
253

4.

Code

/* palindrome.cpp
 * Program that prints if an input number is a palindrome or not.
 *
 * Saggi Mizrahi 5 November 2013
 */

#include <iostream>

using namespace std;

/* Input: A number.
 * Output: outputs whether the input number is palindrome or not.
 */
int main() {
    // declaration of variables
    int number = 0;
    int mirrorNumber = 0;

    // collect input
    cout << "please enter a number: ";
    cin >> number;

    // Create mirrored number
    for (int tmp = number; tmp > 0; tmp /= 10) {
        mirrorNumber *= 10;
        mirrorNumber += tmp % 10;
    }

    // Output results
    cout << number << " is ";
    if (mirrorNumber != number) {
        cout << "not ";
    }
    cout << "a palindrome" << endl;

    return 0;
}

Outputs

please enter a number: 5073705
5073705 is a palindrome

please enter a number: 507375
507375 is not a palindrome