Question

..\111.C(149): warning C290: missing return value求助高手！菜鸟在线等！！

#include <reg51.h>
#include <stdio.h>
#define uchar unsigned char
uchar xdata r_buf[9];
uchar xdata t_buf[3];
uchar xdata send[3];
uchar r_in,r_out,t_in,t_out;
bit r_full,t_empty,t_done;
sbit p0_0=P1^0;
sbit p0_1=P1^1;
sbit p0_2=P1^2;
serial()interrupt 4 using 1 {/通信/
if (RI&&~r_full){
r_buf[r_in]=SBUF;
RI=0;
r_in=++r_in&0x0f;
if(r_in==r_out)r_full=1;
}
else if (TI&&~t_empty) {
SBUF=t_buf[t_out];
TI=0;
t_out=++t_out&0x0f;
if(t_out==t_in)t_empty=1;
}
else if (TI) {
TI=0;
t_done=1;
}
}
void loadmsg(uchar *msg) {/发送缓存/
while ((*msg!=0)&&((((t_in+1)^t_out)&0x0f)!=0)) {
t_buf[t_in]=*msg;
msg++;
t_in=++t_in&0x0f;
if (t_done) {
TI=1;
t_empty=t_done=0;
}
}
}
void process (uchar i,j) {/运行程序，控制三个口开关/
switch(i)
{
case 0x01: {
if(j==0x01) p0_0=1;
else if(j==0x02) p0_1=1;
else if(j==0x03) p0_2=1;
else {TI=1;
printf("error\n");
while(!TI);
TI=0;
};
}break;
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
字数限制省略一段= =#
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
case 0x07: break;
default : {TI=1;
printf("error\n");
while(!TI);
TI=0;
};
}
TI=1;
printf("p0_0=%d,p0_1=%d,p0_2=%d\n",p0_0,p0_1,p0_2);
while(!TI);
TI=0;
}
void processmsg (void) {/接收/
while (((r_out+1)^r_in)!=0) {
r_out=++r_out&0x0f;
}
}
main() {/先接收，再取数据运行程序，再将结果给发送缓存发送/
IE=0;
TMOD=0x20;
TH1=0xfd;
TCON=0x40;
SCON=0x50;
TR1=1;
IE=0x90;
t_empty=t_done=1;
r_full=0;
r_out=t_in=t_out=0;
r_in=1;
p0_0=0,p0_1=0,p0_2=0;
for(;r_full!=1;) {
processmsg();
}
process (r_buf[4],r_buf[5]);
send[0]=p0_0;
send[1]=p0_1;
send[2]=p0_2;
loadmsg (&send[0]);
}
编译警告少返回值，求高人指点具体哪行需改动，先谢谢了啊
Build target 'Target 1'
assembling STARTUP.A51...
compiling 111.c...
..\111.C(149): warning C290: missing return value
linking...
Program Size: data=36.4 xdata=15 code=1795
"111" - 0 Error(s), 1 Warning(s).

Answer 1

这个warning可以不用管，其实是编译器认为你的main()“应该”返回点什么。
你如果受不了编译器的这个唠叨，把main()改成void main()就行了，或者在main()结束前加个
return 0;编译器就happy了。

Answer 2

你解决了没教教我也