从1+3+5+到55，不是这样嘛？

#include "stdio.h"
void main()
{int s=0,n=1;
do
s=s+n,
n=n+2;
while(s<=55);
printf("s=%d",s);
}

do后的内容要加大括号，然后while条件应该是n<=55

#include <stdio.h>
int main()
{int s=0,n=1;
do
{s=s+n;
n=n+2;}
while(n<=55);
printf("s=%d",s);
}

结合上面的兄弟改动，再把 while(s<=55); 改为 while(s<=53);

#include<stdio.h>

int main()
{
int n=55;
printf("%f\r\n",(n+1)/2*(1+n)/2.0);
return 0;
}