Menu?

How do i create options, almost like a menu?
I am planning to make a calculator program that works like this:
1:Person will pick from a menu, 1)Multiply,2)divide, etc., etc.
2: Program will ask for two numbers, depending on what option person picked, program will complete the function.....

all i need help with is creating a menu, and how do i set a variable so that it can be a decimal number?

A simple menu-based program.

Code:

#include <string>
#include <iostream>
using namespace std;

bool StringToInt( string s, int& pInt );
int  menu();

int main(int argc, char *argv[])
{
  string line;
  int choice = menu();
  cout << "Your choice: " << choice << endl;
  cout << "Press Return to continue..." ;
  getline( cin, line );  
}

/*
 *  Displays the menu and allows the user to make a choice.
 */
int menu()
{
  int choice;
  string line;
  
  while( true )
  {
    cout << "\nChoose your favourite hero!\n\n"
            "  1\tBatman\n\n"
            "  2\tSpiderman\n\n"
            "  3\tThe Incredible Hulk\n\n"
            "  4\tWolverine\n\n"
            "  5\tBritney Spears\n\n"
            "Your choice [a/b/c/d]: ";
    
    getline( cin, line );
    
    if( StringToInt(line, choice) == true )
    {
      if( choice < 0 || choice > 5 )
        cout << "Please only enter numbers between 0 to 5 !\n";
      else
        return choice;
    }      
    else
      cout << "Please only enter integers!\n";

    cout << "Press Return to continue..." ;
    getline( cin, line );
  }
}

/**
 *  Converts a string to an integer.
 *  If the conversion fails, return false.
 */
bool StringToInt( string s, int& pInt )
{
  char * end ;
  const char* start = s.c_str();
  pInt = strtol( start, &end, 0 );
 
  if ( start == end )   // end pointer left at start; totally invalid number
    return false;
 
  if ( *end )           // end pointer left in middle; partially invalid number
    return false;
   
  return true;          // end pointer left at end; a valid number
}

and how do i set a variable so that it can be a decimal number?

Use a float or double type.

thanks man but how do you use a float or a doubly type?

Code:

float num = 2.0f;

Surely if someone is new, a switch statment would be easier to follow and understand?

Only because a menu using a swtich statment is a lot more simple then that one.

Chris

You still need to read the input and ensure that it's a proper integer.

And he can use the menu() function in a switch statement.

Code:

switch( menu() )
{
  case 1: /* batman */
  ...
  ...
}

There's a lot of code there for something as simple as a menu, here's the basic outline of what i use, so far it's done the basic tasks i want it to do.

Code:

int i;
cout<< "1. Option one";
cout<< "2. Option two";
cout<< "3. Option three";
cout<< "Choice: "  // The couts will print out your menu
cin>> i; //reads your choice
switch (i)
{
            Case 1: // Executes what you want if number one is pressed
                       blah blah
                       break;
            Case 2: // Executes what you want if number two is pressed
                       blah blah
                       break;
            Case 3: // etc
                       blah blah
                       break;
}

There's a lot of code there for something as simple as a menu, here's the basic outline of what i use, so far it's done the basic tasks i want it to do.

Originally Posted by Dante

You still need to read the input and ensure that it's a proper integer.

If a non-integer is entered, your menu will most likely go into an infinite loop and flash by a million times a minute until you kill the process. Although, as long as you never enter 'bad' choices, that shouldn't be a problem.

Hunter2: you have a point there mate, i must have missed that part, but it shouldnt be a problem as long as only integers are entered......cant say im too good with input validation at the minute though so i cant give any advice on that area