这个题老提示floating point error，到底哪里错了啊？

Question

#include<stdio.h>
double fun(double x);
main()
{
double a,b;
scanf("%f",&a);
b=fun(a);
printf("%f\n",b);
}

double fun(double x)
{
double y;
if (x<-1)
y=x*x-1;
else
if (x<=1)
y=x*x;
else
y=x*x+1;
return(y);
}

Answer 1

scanf("%f",&a);%f代表是float类型，与定义的double类型不合。

Answer 2

scan()函数中：%f对应是float类型，%lf对应的是 double类型printf()函数中：%f即对应float类型也对应double类型#include<stdio.h>double fun(double x);main(){double a,b;scanf("%lf",&a);b=fun(a);printf("%f\n",b);}double fun(double x){double y;if (x<-1)y=x*x-1;elseif (x<=1)y=x*x;elsey=x*x+1;return(y);}结果：输入：10显示：101

Answer 3

%f改成%lf看看