Question

C语言中error C2065:'C2':undeclared identifier是什么意思

#include<stdio.h>
void main()
{
int a,b,c;
long int u,n;
float x,y,z;
char c1,c2;
a=3;b=4;c=5;
x=1.2f;y=2.4f;z=-3.6f;
u=51274;n=128765;
c1='a';c2='b';
printf("\n");
printf("a=%2db=%2dc=%2d\n",a,b,c);
printf("x=%8.6f,y=%8.6f,z=%9.6f\n",x,y,z);
printf("x+y=%5.2fy+z=%5.2fz+x=%5.2f\n",x+y,y+z,z+x);
printf("u=%6ldn=%9ld\n",u,n);
printf("c1='%c' or %d(ASCII)\n",c1,c1);
printf("c2='%c' or %d(ASCII)\n",C2,C2);
}
出错处是
printf("c2='%c' or %d(ASCII)\n",C2,C2);

Answer 1

编译器是区分大小写的
你最后的那个printf("c2='%c' or %d(ASCII)\n",C2,C2);里面的C2是大写的,识别不出来,所以编译错误就是未定义的变量.

Answer 2

注意大小写，出错改为：printf("c2='%c' or %d(ASCII)\n",c2,c2);

Answer 3

C2改成小写就好了啊