从用户读取上限，使用while循环查找前n个整数的

#include <stdio.h>  
int main(voID)    
{  
  int count, sum;              
  int n;  

  printf("Enter the upper limit: ");  
  scanf("%d", &n);  
  count = 0;                    
  sum = 0;                    
  while (count++ < n)  
     sum = sum + count;   
  printf("sum = %d\n", sum);  
  return 0;  
}