新人求助，为什么总是有个一错误

include <stdio.h>
void main()
{
int a,b,sun;
a=123;b=231;
sum=a+b;
printf("sum is %d\n",sum);
}

------------------Configuration: sj - Win32 Debug--------------------
Compiling...
sj.cpp
C:\Users\Administrator\Desktop\程序\sj.cpp(6) : error C2065: 'sum' : undeclared identifier
执行 cl.exe 时出错.sj.obj - 1 error(s), 0 warning(s)

int a,b,sun;
int a,b,sum;

sun 和sum....

楼上正解

我菜了
3q

sun!=sum;

include <stdio.h>
int main(void)
{
int a,b,sun;
a=123;b=231;
sun=a+b;
printf("sum is %d\n"sun);
getch()
} 我的是 WIN-TC 我把这个改啦 哪错啦

include <stdio.h>
int main(void)
{
int a,b,sun;
a=123;b=231;
sun=a+b;
printf("sum is %d\n"sun);
getch()； 继续错

#include <stdio.h>
int main(void)
{
int a,b,sun;
a=123;b=231;
sun=a+b;
printf("sum is %d\n"sun);
getch();
} 继续错

为什么啊

楼主还差 #