C Program to find Sum of natural numbers in given range

#include<stdio.h>
int main()
{
	int start, end, sum=0, i;

	printf("Enter Start Number for Sum: ");
	scanf("%d",&start);
	printf("Enter End Number for Sum: ");
	scanf("%d",&end);

	for(i=start;i<=end;i++)
	{
		sum += i;
	}
	printf("%d",sum);

	return 0;
}

Output

Enter Start Number for Sum: 10
Enter End Number for Sum: 20
165