C++ Programs to Add Two Numbers

How to add two numbers in C++

In this short tutorial, I will show you how to add two numbers in C++.

• First program: Adds two variable values
• Second Program: User is asked to enter two numbers to get the sum
• Third Program: Class is used with two functions to add user-entered two numbers
• and more

1. C++ First program to add to variable values

1. We have three variables i, j, and sum
2. Variable i and j are assigned int values
3. The next line adds the values of variables i and j; their total is assigned to the variable sum.

The code:

#include <iostream>

using namespace std;

int main() {

  int i, j, sum;

  i = 50;

  j = 75;

  sum = i + j;

  cout << sum;

  cout << "The sum of two numbers = " << sum;

  return 0;

}

Output:

2. Taking user input and adding two numbers program

In this program:

• We ask the user to enter two int numbers
• We assigned the entered numbers to two variables i and j
• The values of two variables are added and the sum is assigned to the variable sum

The code:

#include <iostream>

using namespace std;

int main() {

  int i, j, sum;

  cout << "Please enter two numbers\n ";

  cin >> i >> j; //Taking user input

  sum = i+ j;

  // prints sum

  cout << "Sum of Two Numbers = " << sum;

  return 0;

}

Sample output:

3. Adding two real numbers program

The following program adds two real numbers (float) after taking the user input.

• We declared three variables of float type
• Ask the user to enter two real numbers
• Get the sum and display it on the screen

The program

#include <iostream>

using namespace std;

int main() {

  float i, j, sum; //Declaring three float variables

  cout << "Please enter two real numbers\n ";

  cin >> i >> j; //Taking user input for real numbers

  sum = i+ j;

  // prints sum

  cout << "Sum of Two float Numbers = " << sum;
  return 0;

}

Sample Output:

4. Using a function to add two numbers

Let us add two numbers while tasting how to write a simple function in C++.

• Again, we will take two numbers as input from the user
• The numbers are sent to the function (sumFunc)
• The sumFunc function returns the sum of those two numbers
• We will finally display the sum of two numbers on the screen

The code:

#include<iostream>

using namespace std;

int SumFunc(int, int);

int main()

{

    int i, j, sum;

    //Asking user to enter numbers

    cout<<"Please enter two int numbers: \n";

    cin>>i>>j;

    //Calling the SumFunc function

    sum = SumFunc(i, j);


    cout<<"The Sum of Two float Numbers = "<<sum;

    return 0;

}

int SumFunc(int x, int y)

{

    return (x+y);

}

A sample output:

5. Using C++ Class to add two numbers

You might get the assignment to write a simple class in C++ for adding two numbers. So, I will show you how you can do it easily.

The code:

#include <iostream>

using namespace std;

class SumCls {

  int i, j;

public:

  void enterNum() {

    cout << "Please enter two numbers\n";

    cin >> i >> j;

  }

  void getSum() {

    cout << "Sum of Two Numbers = " << i + j;

  }
};

int main()

{

   SumCls m;

   m.enterNum();
   m.getSum();

   return 0;
}

A sample of the above code:

6. Sum of two numbers with an array example

In this program,

• We created an array of three elements
• The first two elements are assigned two int numbers that we want to get the sum
• Third element stores the sum of the first two elements
• We display the result i.e. third element

The program:

#include <iostream>

using namespace std;

int main() {

   int arrSum[3]; //Declaring an int type array of 3 elements

   arrSum[0]=10;
   arrSum[1]=20;
   arrSum[2]=arrSum[0] + arrSum[1];

   //Display result

   cout<<"Sum of "<<arrSum[0]<<" and "<<arrSum[1]<<" is \n"<<arrSum[2];

   return 0;

}

Output: