c语言求助！感激不尽

只看该作者 · 2013-9-7 19:10

今天写了一个流水灯程序，刚开始思路还不错，这个程序写成功了。当我再回头来想改进的时候，在主函数中添加了一个变量来接收函数的返回值的时候，编译没有问题，一切都变了：流水灯不再按照预先那样工作了，而且当你按键的时候，灯在不停的闪烁。（除主函数外，其余都一样）希望有人能伸出友爱之手，把我从疑惑的边缘解救，无以为报，谢谢！！！
错误问题程序
#include <reg51.h>
#include <intrins.h>
void delay(unsigned char ms);
void process(unsigned char key_cess);
unsigned char key_scan();
sbit K1=P0^0;
sbit K2=P0^1;
main()
{
      unsigned char key_cess,K3,key_s;
      P2=0xfe;
      K3=0x03;
      while(1)
      {
            key_s=key_scan();
            if(K3!=key_s)
            {
                     delay(10);
                     key_s=key_scan();
                     if(key_s!=K3)
                     {
                              key_cess=key_s;
                              process(key_cess);
                     }
            }
      }
}
unsigned char key_scan()
{
      unsigned char key_s;
      key_s=0x00;
      key_s |=K2;
      key_s <<=1;
      key_s |=K1;
      return key_s;
}
void process(unsigned char key_cess)
{
      if((key_cess & 0x01) == 0)
      {
            P2 = _cror_(P2,1);
      }
      else if((key_cess & 0x02) == 0)
      {
            P2 = _crol_(P2, 1);
      }
}
void delay(unsigned char ms)
{
      unsigned char i;
      while(ms--)
      {
            for(i = 0; i < 120; i++);
      }
}

正确程序：
#include <reg51.h>
#include <intrins.h>
void delay(unsigned char ms);
void process(unsigned char key_cess);
unsigned char key_scan();
sbit K1=P0^0;
sbit K2=P0^1;
main()
{
      unsigned char key_cess,key_s;
      P2=0xfe;
      key_cess=0x03;
      while(1)
      {
            key_s=key_scan();
            if(key_cess!=key_s)
            {
                     delay(10);
                     key_s=key_scan();
                     if(key_s!=key_cess)
                     {
                              key_cess=key_s;
                              process(key_cess);
                     }
            }
      }
}
unsigned char key_scan()
{
      unsigned char key_s;
      key_s=0x00;
      key_s |=K2;
      key_s <<=1;
      key_s |=K1;
      return key_s;
}
void process(unsigned char key_cess)
{
      if((key_cess & 0x01) == 0)
      {
            P2 = _cror_(P2,1);
      }
      else if((key_cess & 0x02) == 0)
      {
            P2 = _crol_(P2, 1);
      }
}
void delay(unsigned char ms)
{
      unsigned char i;
      while(ms--)
      {
            for(i = 0; i < 120; i++);
      }
}