刚学单片机没多久，看宋师傅的视频刚学到按键这一块。编译的时候，提示“main.c(30): error C141: syntax error near 'unsigned'”，是“u8 cnt = 0;”这一行定义变量出错，发现放在main函数前面就没问题。“cnt”这个不是局部变量吗？为啥放main函数里面编译会出错？另外，发现定义的bit变量必须放main函数的最上面，不然编译也会出错，是什么问题？
#include<reg52.h> //此文件中定义了单片机的一些特殊功能寄存器
sbit LED1=P2^2;
sbit LED2=P2^3;
sbit LED3=P2^4;
sbit G1=P1^7;
sbit S1=P1^3;
#define u16 unsigned int //对数据类型进行声明定义
#define u8 unsigned char
u8 code ledchar[]={
0x3f,0x06,0x5b,0x4f,
0x66,0x6d,0x7d,0x07,
0x7f,0x6f,0x77,0x7c,
0x39,0x5e,0x79,0x71};
void delay(u16 i);
void main()
{
bit backup = 1;
bit keybuff = 1;
LED1=0;
LED2=0;
LED3=0;
G1=0;
u8 cnt = 0;
P0=ledchar[cnt];
while(1)
{
keybuff = S1;
if(keybuff != backup)
{
delay(1000);
if(keybuff == S1)
{
if(backup==0)
{
cnt++;
if(cnt>=10)
{
cnt=0;
}
P0=ledchar[cnt];
}
backup = S1;
}
}
}
}
void delay(u16 i)
{
while(i--);
}
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