C Program to Find Sum of n Natural Numbers

//C Program to Find the Sum of n Natural Numbers Using For loop

#include<stdio.h>
int main()
{
 //Declaring Variable
  int n, i, sum = 0 ;
 
//Input Number
 printf("Enter a Number\n");
  scanf("%d",&n);
 
 for(i=1;i<=n;i++)
  {
      sum = sum + i;
  }
  printf("\nSum of %d Natural Numbers = %d",n, sum);
  return 0;
}

Output

Enter a Number
5

Sum of 5 Natural Numbers = 15

Program Explanation

In this program, we first declared three variables of int data type named i, n, sum.
After that, we take a number input from the user.
Then we calculate the sum of n natural numbers.
after Calculating Sum we print it on the screen through print().

C Program to Find the Sum of n Natural Numbers Using While Loop

Algorithm

Program Start
Variable Declaration
Input a Number from the User
Calculating Sum of n Naturals Numbers
Displaying the Sum of n Naturals Numbers
Program End

Program

//C Program to Find the Sum of n Natural Numbers Using While Loop

#include<stdio.h>
void main()
{
  int n, i=1, sum = 0 ;
  printf("Enter a Number\n");
  scanf("%d",&n);

  while(i<=n)
  {
      sum = sum + i;
      i++;
  }
  printf("\nSum of %d Natural Numbers = %d",n, sum);
}

Output

Enter a Number
10

Sum of 10 Natural Numers = 55

C Program to Find the Sum of n Natural Numbers Using Do While Loop

Program

//C Program to Find the Sum of n Natural Numbers Using Do While Loop

#include<stdio.h>
int main()
{
  int n, i=1, sum = 0 ;
  printf("Enter A Number to Calculate Sum\n");
  scanf("%d",&n);
do
  {
      sum = sum + i;
      i++;
  }while(i<=n);

  printf("\nSum of %d Natural Numbers = %d",n, sum);

return 0;
}

Output

Enter  A Number to Calculate Sum
15

Sum of 15 Natural Numbers = 120

C Program to Find the Sum of n Natural Numbers Using Function

To Calculate the sum n natural numbers through a function, first you need to know about the function. You can read about the function from the link given below.

Function in C

Algorithm

Program Start
Declaring variables
Input Number
Calling Function to calculate Sum of n Natural Numbers
Print the Sum of n Numbers
Program End

Program

//C Program to Find the Sum of n Natural Numbers Using function

#include<stdio.h>
int sum(int);
void main()
{
  int n, i=1, s;
  
 printf("Enter A Number\n");
  scanf("%d",&n);
 
  s=sum(n);
  printf("\nSum of %d Natural Numbers = %d",n, s);
}
int sum(int n)
{
    int i,sum=0;
    for(i=1;i<=n;i++)
    {
        sum = sum + i;
    }
    return (sum);
}

Output

Enter A Number 
20

Sum of 20 Natural Numbers = 210

C Program to Find the Sum of n Natural Numbers Using Recursion

To Calculate the sum n natural numbers through a Recursion, first you need to know about the Recursion. You can read about the Recursion from the link given below.

Recursion in C

Algorithm

Program Start
Declaring variables
Input Number
Calling Recursive Function to calculate Sum of N Natural Numbers
Print the Sum of n Natural Numbers
Program End

Program

//C Program to Find the Sum of n Natural Numbers Using Recursion

#include<stdio.h>
int sum(int);
void main()
{
  int n, s;

 printf("Enter A Number\n");
  scanf("%d",&n);

  s=sum(n);
  printf("\nSum of %d Natural Numbers = %d",n, s);
}
int sum(int n)
{
    int s=0;

    if(n==1)
        return (n);

    s = n + sum(n-1);
     return (s);
}

Output

Enter a Number
25

Sum of 25 Natural Numbers = 325

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Conclusion

So friends, in this article, we have written a program to calculate the sum n natural numbers in five different ways.

C Program to Find the Sum of n Natural Numbers Using For Loop
C Program to Find the Sum of n Natural Numbers Using While Loop
C Program to Find the Sum of n Natural Numbers Using Do While Loop
C Program to Find the Sum of n Natural Numbers Using Function
C Program to Find the Sum of n Natural Numbers Using Recursion

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