到底哪里错了啊啊啊啊啊#include<stdio.h>
int main()
{
float x,y;
scanf("%f\n",&x);
if(x<0)
{y=0;
printf("y=%f\n",y);}
else
if(x>=0&&x<10)
{y=x;
printf("y=%f\n",y);}
else
if(x>=10&&x<20)
{y=10;
printf("y=%f\n",y);}
else
if(x>=20&&x<40)
{y=-0.5*x+20;
printf("y=%f\n",y);}
else
printf("输入的x值有误");
return 0;
}
