#include<iostream>
using namespace std;
void function_addition();
void function_subtraction();
void function_multiplication();
void function_division();
int main()
{
void (* point_function[4])();
point_function[0]=function_addition;
point_function[1]=function_subtraction;
point_function[2]=function_multiplication;
point_function[3]=function_division;
int i;
while(1)
{
cout<<"put the i"<<endl;
cout<<"0---addition"<<endl;
cout<<"1---subtraction"<<endl;
cout<<"2---multiplication"<<endl;
cout<<"3---division"<<endl;
cout<<endl;
cin>>i;
if(i!=0&&i!=1&&i!=2&&i!=3)
{
cout<<"please input again";
cin>>i;
}
point_function[i]();
}
return 0;
}
void function_addition()
{
cout<<"this is addition:"<<endl<<"pleace put two num"<<endl;
double a,b;
cin>>a>>b;
cout<<a+b<<endl<<endl;
}
void function_subtraction()
{
cout<<"this is subtraction:"<<endl<<"pleace put two num"<<endl;
double a,b;
cin>>a>>b;
cout<<a-b<<endl<<endl;
}
void function_multiplication()
{
cout<<"this is multiplication:"<<endl<<"pleace put two num"<<endl;
double a,b;
cin>>a>>b;
cout<<a*b<<endl<<endl;
}
void function_division()
{
cout<<"this is division:"<<endl<<"pleace put two num"<<endl;
double a,b;
cin>>a>>b;
cout<<a/b<<endl<<endl;
}