C++: Practicing programs

#include <iostream>

using namespace std;

// Function prototype (declaration)

int add(int, int);

int main()

{

    int num1, num2, sum;

    cout<<"Enters two numbers to add: ";

    cin >> num1 >> num2;

    // Function call

    sum = add(num1, num2);

    cout << "Sum = " << sum;

    return 0;

}

// Function definition

int add(int a, int b)

{

    int add;

    add = a + b;

    // Return statement

    return add;

}

#include <iostream>

using namespace std;

void prime(int n);

int main()

{

    int num;

    cout << "Enter a positive integer to check: ";

    cin >> num;

    // Argument num is passed to the function prime()

    prime(num);

    return 0;

}

// There is no return value to calling function. Hence, return type of function is void. */

void prime(int n)

{

    int i, flag = 0;

    for (i = 2; i <= n/2; ++i)

    {

        if (n%i == 0)

        {

            flag = 1;

            break;

        }

    }

    if (flag == 1)

    {

        cout << n << " is not a prime number.";

    }

    else {

        cout << n << " is a prime number.";

    }

}

#include <iostream>

using namespace std;

int absolute(int);

float absolute(float);

int main() {

    int a = -5;

    float b = 5.5;

    cout << "Absolute value of " << a << " = " << absolute(a) << endl;

    cout << "Absolute value of " << b << " = " << absolute(b);

    return 0;

}

int absolute(int var) {

     if (var < 0)

         var = -var;

    return var;

}

float absolute(float var){

    if (var < 0.0)

        var = -var;

    return var;

}

#include <iostream>

using namespace std;

void display(char = '*', int = 1);

int main()

{

    cout << "No argument passed:\n";

    display();

    cout << "\nFirst argument passed:\n";

    display('#');

    cout << "\nBoth argument passed:\n";

    display('$', 5);

    return 0;

}

void display(char c, int n)

{

    for(int i = 1; i <= n; ++i)

    {

        cout << c;

    }

    cout << endl;

}

#include <iostream>

using namespace std;

int factorial(int);

int main() 

{

    int n;

    cout<<"Enter a number to find factorial: ";

    cin >> n;

    cout << "Factorial of " << n <<" = " << factorial(n);

    return 0;

}

int factorial(int n) 

{

    if (n > 1) 

    {

        return n*factorial(n-1);

    }

    else 

    {

        return 1;

    }

}

#include <iostream>

using namespace std;

int main() 

{

    int numbers[5], sum = 0;

    cout << "Enter 5 numbers: ";

    //  Storing 5 number entered by user in an array

    //  Finding the sum of numbers entered

    for (int i = 0; i < 5; ++i) 

    {

        cin >> numbers[i];

        sum += numbers[i];

    }

    cout << "Sum = " << sum << endl;  

    return 0;

}

#include <iostream>

using namespace std;

const int CITY = 2;

const int WEEK = 7;

int main()

{

    int temperature[CITY][WEEK];

    cout << "Enter all temperature for a week of first city and then second city. \n";

    // Inserting the values into the temperature array

    for (int i = 0; i < CITY; ++i)

    {

        for(int j = 0; j < WEEK; ++j)

        {

            cout << "City " << i + 1 << ", Day " << j + 1 << " : ";

            cin >> temperature[i][j];

        }

    }

    cout << "\n\nDisplaying Values:\n";

    // Accessing the values from the temperature array

    for (int i = 0; i < CITY; ++i)

    {

        for(int j = 0; j < WEEK; ++j)

        {

            cout << "City " << i + 1 << ", Day " << j + 1 << " = " << temperature[i][j] << endl;

        }

    }

    return 0;

}

#include <iostream>

using namespace std;

int main()

{

    // This array can store upto 12 elements (2x3x2)

    int test[2][3][2];

    cout << "Enter 12 values: \n";

    // Inserting the values into the test array

    // using 3 nested for loops.

    for(int i = 0; i < 2; ++i)

    {

        for (int j = 0; j < 3; ++j)

        {

            for(int k = 0; k < 2; ++k )

            {

                cin >> test[i][j][k];

            }

        }

    }

    cout<<"\nDisplaying Value stored:"<<endl;

    // Displaying the values with proper index.

    for(int i = 0; i < 2; ++i)

    {

        for (int j = 0; j < 3; ++j)

        {

            for(int k = 0; k < 2; ++k)

            {

                cout << "test[" << i << "][" << j << "][" << k << "] = " << test[i][j][k] << endl;

            }

        }

    }

    return 0;

}

#include <iostream>

using namespace std;

void display(int n[3][2]);

int main()

{

    int num[3][2] = {

        {3, 4},

        {9, 5},

        {7, 1}

    };

    display(num);

    return 0;

}

void display(int n[3][2])

{

    cout << "Displaying Values: " << endl;

    for(int i = 0;  i < 3; ++i)

    {

        for(int j = 0; j < 2; ++j)

        {

            cout << n[i][j] << " ";

        }

    }

}

#include <iostream>

using namespace std;

int main()

{

    char str[100];

    cout << "Enter a string: ";

    cin.get(str, 100);

    cout << "You entered: " << str << endl;

    return 0;

}

#include <iostream>

using namespace std;

void display(char *);

void display(string);

int main()

{

    string str1;

    char str[100];

    cout << "Enter a string: ";

    getline(cin, str1);

    cout << "Enter another string: ";

    cin.get(str, 100, '\n');

    display(str1);

    display(str);

    return 0;

}

void display(char s[])

{

    cout << "Entered char array is: " << s << endl;

}

void display(string s)

{

    cout << "Entered string is: " << s << endl;

}