#include
#define pi 3.1415926
void main()
{double r;
double s=0.0;
for(r=1;r<=10;r++)
{s=pi*r*r;
if(s>=100)break;}
printf("r=%f\n,s=%f",r,s);
}
错误是--------------------Configuration: jin - Win32 Debug--------------------
Compiling...
jin1.cpp
Linking...
LIBCD.lib(wincrt0.obj) : error LNK2001: unresolved external symbol _WinMain@16
Debug/jin.exe : fatal error LNK1120: 1 unresolved externals
Error executing link.exe.

jin.exe - 2 error(s), 0 warning(s)
求解。谢谢。

新建工程的时候应该选Win32 console Application，你选的是Win32 Application吧。
另外#include后面要写完。

dui,#include<stdio.h>

类型不符double rfor(r=1;r<=10;r++)