system(cls);老是出错，改了几遍？？不知道哪里错了
#include<stdio.h>#include<string.h>
#include <conio.h>
void main()
{
static char c1[10]="abcdefghi",c2[]="china";
strcpy(c1,c2);
system(c1s);
puts(c1);
printf("%c",c1[7]);
}
1234.cpp
C:\446\1234.cpp(9) : error C2065: 'system' : undeclared identifier
C:\446\1234.cpp(9) : error C2065: 'c1s' : undeclared identifier
执行 cl.exe 时出错.
