参考程序: 1. #include <iostream . h> void main(t float,y; cout<<"请输入一个实数:"; if(x<=2.5)y=1.5*x+7.5 sey=9.32*x-342 cout<<”x=<x<t<s"y=”<<y<<n include <iostream. h> void main(i float cout<"请输入两个实数: if(x>y)cout<<x-y=<<x-y<<in else cout<<"y-x<<y-X<<in参考程序： 1．#include <iostream.h> void main(){ float x,y; cout<<"请输入一个实数："; cin>>x; if(x<=2.5)y=1.5*x+7.5; else y=9.32*x-34.2; cout<<”x=”<<x<<'\t'<<”y=”<<y<<'\n'; } 2． #include <iostream.h> void main(){ float x,y; cout<<"请输入两个实数："; cin>>x; cin>>y; if(x>y)cout<<"x-y="<<x-y<<'\n'; else cout<<"y-x="<<y-x<<'\n'; }