程序： #include   //头文件 #define uint unsigned int // #define uchar unsigned char sbit lcden=P2^3; //定义引脚 sbit rs=P2^4; sbit rw=P2^0; sbit busy=P0^7; char i,j,temp,num,num_1; long a,b,c;     //a,第一个数 b,第二个数 c,得数 float a_c,b_c; uchar flag,fuhao;//flag表示是否有符号键按下，fuhao表征按下的是哪个符号 uchar code table[]={ 7,8,9,0, 4,5,6,0, 1,2,3,0, 0,0,0,0}; uchar code table1[]={ 7,8,9,0x2f-0x30, 4,5,6,0x2a-0x30, 1,2,3,0x2d-0x30, 0x01-0x30,0,0x3d-0x30,0x2b-0x30}; void delay(uchar z) // 延迟函数 { uchar y; for(z;z>0;z--)    for(y=0;y