# C Program to calculate sum of ODD numbers till N

Get input n and calculate the sum of odd numbers till n

Sample Input 1:

5

Sample Output 1:

9(1+3+5)

#### Program or Solution

#include<stdio.h> int main() { int n,i,sum=0; printf("Enter a number:"); scanf("%d",&n); for(i=1;i<=n;i=i+2) { sum=sum+i; } printf("The sum of first %d odd numbers: %d",n,sum); return 0; }

#### Program Explanation

Instruction(s) inside the for block{} are executed repeatedly till the second expression (i<=n) is true.

Here i is initialized to 1 and incremented by 2 for each iteration, instructions inside the **for** block are executed unless i becomes greater than n.

so value of i (1,3,5,...n)will be added to sum.

after adding all n odd numbers to sum, sum will be printed using printf statement.