上机作业2-2，3，4

#include<iostream>
using namespace std;
int main()
{
    double x,y;
    cin>>x;
    if(x>=1)
        {
            y=x-1;
            cout<<y;
        }
    else
    {
        y=1-x;
        cout<<y;
    }
	return 0;
#include<iostream>
using namespac