sum of (1+2+3...........99+100)

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

  for(a=1; a<=100; a++)
{
printf("%d",a);

sum = sum+a;

if(a<100)
{
  printf(" + ");
}
}
printf(" = %d", sum);

printf("\n\n");

  return 0;
}