help with switch statement

**volk** · 03-17-2003

Why doesn't the following code work?

Code:

#include <iostream>
using namespace std;

int main()

{
	char switchstart;

	cout << "Enter your desired color" << endl;

	enum{black = 0, blue = 1, green = 2, red = 4, purple = 5, yellow = 6, white = 7, gray = 8};

	for ( ; ; )
	{
	
		cin >> switchstart;
	
		switch (switchstart)
	{
	case black:
		system ("color 0F");
		break;

	case blue:
		system ("color 1F");
		break;

	case green:
		system ("color 2F");
		break;

	case red:
		system ("color 4F");
		break;

	case purple:
		system ("color 5F");
		break;

	case yellow:
		system ("color 60");
		break;

	case white:
		system ("color 70");
		break;

	case gray:
		system ("color 8F");
		break;
	}
	}


	return 0;

}

**Hammer** · 03-17-2003

Because 1 isn't the same as '1'.

Make this:
char switchstart;
into this:
int switchstart;

**volk** · 03-17-2003

I want to type in the word instead of the number. Should I use one of those strange functions like getchar or something instead of cin?

**Kespoosh** · 03-17-2003

I don't claim to be any good at C++, but I believe that you have to have an array, not a char. I think a char will only store one keystroke, whereas an array can store many characters. I think.

**PJYelton** · 03-17-2003

Unfortunately you can't use enums like that. Enums are only for code readability really, not for inputing and outputing. And you can only use int values or equivalent in a switch command. If you want the user to write the word, then the simplest solution would be to use if statements (or a lookup array table):

Code:

string choice;
cout<<"Choose color: ";
cin<<choice;

if (choice=="black")
  // black
else if (choice=="red")
  // red
...

**nextus** · 03-18-2003

isnt it also true that switch statments only work with integers and chars.......? and for the famous WIN32 API

Code:

switch(message)
{
case WM_CREATE:
....
}

message is unsigned int...and the window messages are unsigned int...i think?

**Polymorphic OOP** · 03-18-2003

Originally posted by nextus
isnt it also true that switch statments only work with integers and chars.......?

not true. switch statements work with any integral types (IE enum datatypes).

**Hammer** · 03-18-2003

>>Unfortunately you can't use enums like that
Why not:

Code:

#include <iostream>

using std::cin;
using std::cout;
using std::endl;

int main()
{
  enum COLOURS {black, blue, red, invalid};
  int i = invalid;
  
  cout <<"Enter number (0 to 2):" <<endl;
  cin >>i;
  
  switch (i)
  {
    case black: cout <<"black"; break;
    case blue : cout <<"black"; break;
    case red  : cout <<"black"; break;
    default   : cout <<"Wrong"; break;
  }
  
  cout <<endl;
}

**Polymorphic OOP** · 03-18-2003

Originally posted by Hammer
>>Unfortunately you can't use enums like that
Why not

because he wants the user to be able to type in the name of the color, not its numerical equivalent.

volk, you have to set up a bunch of strings and compare the input data with those and base your results on that. All enum does is create a bunch of constants (and new integral datatypes). You can't compare the names of those constants just like you can't compare the names of variables in your program.

**Hammer** · 03-18-2003

>>because he wants the user to be able to type in the name of the color, not its numerical equivalent.
Doh! I missed that part!

Anyway, something like this might do for you:

Code:

string Colours[] = {"Black", "Blue", "Red"};
string s;
  
cout <<"Enter a colour:" <<endl;
cin >>s;

for (int i = 0; i < sizeof (Colours) / sizeof (Colours[0]); i++)
{
  if (Colours[i] == s)
  {
      // Found a match
  }
}

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