求实数绝对值

参考代码

#include<stdio.h>
double y(double n);
int main()
{
    double n,s;
    while(scanf("%lf",&n)!=EOF)
    {
        s = y(n);
        printf("%.2lf\n",s);
    }
    return 0;
}
double y(double n)
{
    return n >= 0? n:-n;
}