phonekey.cpp

Enter letter and print the corresponding phone key

//**************************************************
//      Filename: phonekey.cpp
//Enter letter and print the corresponding phone key 
//Programming Problems No.4 on P347 of textbook. 
//**************************************************
#include<iostream>

using namespace std;

void Convert(char,bool&);  //To convert letter into telephone number
						   //and print it.
int main()
{
	char inchar;           //The character the user input
	bool quit=false;       //True if the user wants to quit

	do
	{
		cout<<"Enter a letter:";
		cin >>inchar;

		Convert(inchar,quit);
	}while(!quit);
	return 0;
}

void Convert(char inchar,
			 bool& quit)
//While the user has entered a character,test it and if valid,
//convert it into telephone number and print it.
{
	//Test data
	if(inchar=='Q' || inchar=='Z')
	{
		cout<<"Quit."<<endl;
		quit=true;
		return;
	}
	else if(inchar<'A' || inchar>'Z')
	{
		cout<<"Invalid letter. Enter Q or Z to quit."<<endl;
		return;
	}
	//Convert and print
	cout<<"The letter "<<inchar<<" corresponds to ";
	if(inchar=='A' || inchar=='B' || inchar=='C')
		cout<<'2';
	else if(inchar=='D' || inchar=='E' || inchar=='F')
		cout<<'3';
	else if(inchar=='G' || inchar=='H' || inchar=='I')
		cout<<'4';
	else if(inchar=='J' || inchar=='K' || inchar=='L')
		cout<<'5';
	else if(inchar=='M' || inchar=='N' || inchar=='O')
		cout<<'6';
	else if(inchar=='P' || inchar=='R' || inchar=='S')
		cout<<'7';
	else if(inchar=='T' || inchar=='U' || inchar=='V')
		cout<<'8';
	else if(inchar=='W' || inchar=='X' || inchar=='Y')
		cout<<'9';
	cout<<" on the telephone."<<endl;
}