Write a C program to find the sum of all natural numbers between 1 to n using for loop. How to find sum of natural numbers in a given range in C programming. C program to find sum of natural numbers in given range. Logic to find sum of all natural numbers in a given range in C program.

**Example**

**Input**

Input upper limit: 10

**Output**

Sum of natural numbers 1-10: 55

## Required knowledge

## Logic to find sum of natural numbers

I already discussed, how efficiently you can use for loop to iterate over a series. To print all natural numbers. In case you missed, take a quick recap.

Below is the step by step descriptive logic to find sum of n natural numbers.

- Read the upper limit to find sum of natural numbers. Store it in some variable say N.
- Initialize another variable, that will hold sum of numbers. Which is sum = 0.
- Initialize a loop from 1 to N, incrementing 1 on each iteration. The loop structure should be for(i=1; i<=N; i++).
- Inside the loop add the previous sum with the current number i. Which is sum = sum + i.
- Finally after the loop print the value of sum.

## Program to find sum of natural numbers

/** * C program to find sum of natural numbers between 1 to n */ #include <stdio.h> int main() { int i, n, sum=0; /* Read upper limit from user */ printf("Enter upper limit: "); scanf("%d", &n); /* * Find summation of all numbers */ for(i=1; i<=n; i++) { sum += i; } printf("Sum of first %d natural numbers = %d", n, sum); return 0; }

**Note:** sum += i is similar to sum = sum + i. You can use any of them depending on your comfort.

Enter upper limit: 10 Sum of first 10 natural numbers = 55

## Program to find sum of natural numbers in given range

/** * C program to find sum of natural numbers in given range */ #include <stdio.h> int main() { int i, start, end, sum=0; /* Read lower and upper limit from user */ printf("Enter lower limit: "); scanf("%d", &start); printf("Enter upper limit: "); scanf("%d", &end); /* * Find summation of all numbers */ for(i=start; i<=end; i++) { sum += i; } printf("Sum of natural numbers between %d-%d = %d", start, end, sum); return 0; }

Enter lower limit: 10 Enter upper limit: 15 Sum of first 10 natural numbers = 75

Happy coding ;)

### You may also like

- Loop programming exercises index.
- C program to print natural numbers in given range.
- C program to print natural numbers in given range using while loop.
- C program to print natural numbers in reverse.
- C program to print natural numbers using recursion.
- C program to find sum of natural numbers using recursion.

< pre>< code >----Your Source Code---- < / code > < / pre > (Remove spaces from pre and code tags)