This C Program calculates the sum of first N natural numbers.

Here is source code of the C program to calculate the sum of first N natural numbers. The C program is successfully compiled and run on a Linux system. The program output is also shown below.

`/*`

`* C program to find the sum of 'N' natural numbers`

`*/`

`#include <stdio.h>`

void main()

`{`

int i, num, sum = 0;

printf("Enter an integer number \n");

scanf ("%d", &num);

for (i = 1; i <= num; i++)

`{`

sum = sum + i;

`}`

printf ("Sum of first %d natural numbers = %d\n", num, sum);

`}`

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$ cc pgm3.c $ a.out Enter an integer number 1300 Sum of first 1300 natural numbers = 845650 $ a.out Enter an integer number 15 Sum of first 15 natural numbers = 120

**Sanfoundry Global Education & Learning Series – 1000 C Programs.**

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If you wish to look at other example programs on Mathematical Functions, go to C Programming Examples on Mathematical Functions. If you wish to look at programming examples on all topics, go to C Programming Examples.