c语言出现illegal else without matching if 执行 cl.exe 时出错.
#include<stdio.h>#include<math.h>
int main()
{
double a,x,y;
scanf("%lf",&x);
a=10.2;
if(x>=-100,'&&',x<=0);
{
y=sqrt(a*a+x*x);
printf("%lf",y);
else if(x>=0)
y=3*a*x*x+4*a*x-1;
printf("%lf",y);
};
return 0;
};
