C :

#include<stdio.h>
int main(){
int i=1,sum=0;
  do{
  sum+=i;
  i++;
  }while(i<=100);
  printf("%d\n",sum);
return 0;
}

C++ :

#include <stdio.h>
int main() {
	int i, sum;
	sum = 0;
	i = 1;
	do {
		sum += i;
		i++;
	} while (i <= 100);
	printf("%d\n", sum);
	return 0;
}