怎么编写这个分段函数的程序

Question

 

Answer 1

#include<stdio.h>
int main()
{
    int i,x;
    float y;
    scanf("%d",&x);
    if(x<2){
        y=-1*x+2.5;
    }
    else if(x>=4){
        y=0.5*x-1.5;
    }
    else
        y=2-1.5*(x-3)*(x-3);
    printf("%.2f",y);
}