#include <iostream> using namespace std; double func, Sum(), Mult(), Subt(), Div(), Raise(), Roots(), Square(), Avg(), Quit; int main() { double result; cout<<" ***Welcome to my calculator*** "<<endl; cout<<"Select one of the following options: "<<endl; cout<<"\t 1- Add"<<endl; cout<<"\t 2- Multiplication"<<endl; cout<<"\t 3- Subtract"<<endl; cout<<"\t 4- Division"<<endl; cout<<"\t 5- Raise to power"<<endl; cout<<"\t 6- Roots of Polynomial of Second Degree"<<endl; cout<<"\t 7- Square Root"<<endl; cout<<"\t 8- Average"<<endl; cout<<"\t 9- Quit"<<endl; cout<<"Enter a option: "; cin>>func; result=Mult(); cout<<"Result is "<<result<<endl; system("pause"); return 0; } double Mult() { int n, count; double total=1,num; cout<<"How many numbers do you want to calculate: "; cin>>n; for (count=0;count<n;count++) { cout<<"Enter a value: "; cin>>num; total= total*num; } return total; }

Im making the functions on different source files. I make the multiply and add. And I have no idea how to make this. I hope you can help me..