C++ program to calculate the sum of natural numbers

In this tutorial, we will discuss a concept of C++ program to calculate the sum of natural numbers using loops

In this article, we are going to learn how to find the sum of natural numbers using loops in the C++ programming language

C++ code to find the sum of natural numbers using loop

C++ code to find the sum of numbers using for loop

Program 1

This program takes input from the user and stores in variable num. Then, the for loop is used to calculate the sum of natural numbers up to the given numbers.

#include <iostream>
#include <conio.h>
using namespace std;

int main()
{
    int num,i,sum=0;  //variable declaration

    cout<<"Enter a positive integer: ";
    cin>>num;      //get input from user

    for(i=1; i<=num; i++){
        sum+=i;    //sum=sum+i

    }
    cout<<"Sum of numbers are:"<<sum;//display sum of numbers
    getch();
    return 0;
}

When the above code is executed, it produces the following results

Enter a positive integer: 150
Sum of numbers are: 11325

C++ code to find the sum of natural numbers using while loop

Program 2

This program takes input from the user and stores in variable num. Then, the while loop is used to calculate the sum of natural numbers up to the given numbers.

#include <iostream>
#include <conio.h>
using namespace std;

int main()
{
    int num,i,sum=0;

    cout<<"Enter a positive integer: ";
    cin>>num;
i=1;
    while( i<=num){
        sum+=i;    //sum=sum+i
 i++;
    }
    cout<<"Sum of natural numbers are:"<<sum;
    getch();
    return 0;
}

When the above code is executed, it produces the following results

Enter a positive integer: 25
Sum of natrural numbers are: 325

C++ code to find the sum of natural numbers using do-while loop

Program 3

This program takes input from the user and stores in variable num. Then, the do-while loop is used to calculate the sum of natural numbers up to the given numbers.

#include <iostream>
#include <conio.h>
using namespace std;

int main()
{
    int num,i,sum=0;       //1
    cout<<"Enter a positive integer: ";
    cin>>num;              //2
    i=1;

do{        //3

    sum+=i;
     i++;
}
    while(i<=num);
          //sum=sum+i

cout<<"Sum of natural numbers are: "<<sum;      //4

    getch();
    return 0;
}

When the above code is executed, it produces the following results

Enter a positive integer:75
Sum of natural numbers are: 2850

Method:

The following variables i,num and sum=0 are declared.
A positive integer is received from the user.
Then, the loop is used to add a consecutive number from 1 up to the given number.
Finally, the sum is received as total and displayed.