Rand() function
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Thread: Rand() function

  1. #1
    Join Date
    Feb 2011
    Posts
    3

    Question Rand() function

    I'm trying to make a simple console game using Microsoft visual c++ 2010. It is a guessing game in which it creates a random number and you try to guess the number. There are two options, 1 to 10, or 1 to 100. The problem is it keeps generating a new random number every time i guess. I need the number to stay the same throughout the game. Does anyone know what the problem is?

    Here is my code:

    Code:
    #include <iostream>
    #include <time.h>
    
    using namespace std;
    
    void game1();
    void game2();
    
    void main() {
    	cout << "Guess the number" << endl;
    	cout << "----------------" << endl;
    	cout << "Please select an option" << endl;
    	cout << "1. 1 to 10" << endl;
    	cout << "2. 1 to 100" << endl;
    	int selection;
    	cin >> selection;
    	if (selection == 1) {
    		game1();
    	}
    	if (selection == 2) {
    		game2();
    	}
    }
    
    void game1() {
    	system("cls");
    	cout << "Guess the number (1 to 10):" << endl;
    	for (int times = 1;;times++) {
    		char answer;
    		int guess;
    		int number;
    		srand(time(0));
    		number = int(rand() &#37; 10 + 1); 
    		cin >> guess;
    		if (guess == number)
    		{
    			system("cls");
    			cout << "You win!" << endl;
    			cout << "It took you " << times << " times to guess." << endl;
    			cout << "Would you like to play again? (y/n)" << endl;
    			cin >> answer;
    			if (answer = 'y') {
    				game1();
    			}
    			if (answer = 'n') {
    				main();
    			}
    			system("pause");
    		}
    		else
    			if (guess > number) {
    				cout << "The number is less than " << guess << ". Guess the number (1 to 10):" << endl;
    			}
    		else
    			if (guess < number) {
    				cout << "The number is more than " << guess << ". Guess the number (1 to 10):" << endl;
    			}
    
    	}
    }
    
    void game2() {
    	system("cls");
    	cout << "Guess the number (1 to 100):" << endl;
    	for (int times = 1;;times++) {
    		char answer;
    		int guess;
    		int number;
    		srand(time(0));
    		number = int(rand() % 100 + 1); 
    		cin >> guess;
    		if (guess == number)
    		{
    			system("cls");
    			cout << "You win!" << endl;
    			cout << "It took you " << times << " times to guess." << endl;
    			cout << "Would you like to play again? (y/n)" << endl;
    			cin >> answer;
    			if (answer = 'y') {
    				game2();
    			}
    			if (answer = 'n') {
    				main();
    			}
    			system("pause");
    		}
    		else
    			if (guess > number) {
    				cout << "The number is less than " << guess << ". Guess the number (1 to 100):" << endl;
    			}
    		else
    			if (guess < number) {
    				cout << "The number is more than " << guess << ". Guess the number (1 to 100):" << endl;
    			}
    
    	}
    }
    Last edited by Marc G; February 22nd, 2011 at 03:15 AM. Reason: Added code tags

  2. #2
    Join Date
    Jul 2009
    Location
    India
    Posts
    835

    Re: Rand() function

    1st of all use CODE tags around your code and 2nd thing is its a VC++ forum. Post all your further queries relates to C++ in this forum.

    And the solution is to use a 'static variable'. Though I didn't go through your code just posted the ans by reading the txt.

  3. #3
    Join Date
    May 2006
    Location
    Dresden, Germany
    Posts
    458

    Re: Rand() function

    Hi,

    Please use code tags when posting code (see FAQ's for details)!

    srand is menat to be called once (at the start of your program). It initializes the pseudo random generator.

    rand itself can be called as often as you want. In case it should be called exactly when you need a new random number. Then you can hold this value in a variable and make your guesses until you'll have got it.

    With regards
    Programartist

  4. #4
    Join Date
    Feb 2011
    Posts
    3

    Re: Rand() function

    Thank you for your help.

  5. #5
    GCDEF is offline Elite Member Power Poster
    Join Date
    Nov 2003
    Posts
    12,095

    Re: Rand() function

    Also, never, and I mean NEVER call main directly. Never.

    You need to start using loops instead of recursive calls as you're doing. That's really bad design.

    Also, if there's no reason for two different game functions. All you need is one function that knows the upper limit.

  6. #6
    GCDEF is offline Elite Member Power Poster
    Join Date
    Nov 2003
    Posts
    12,095

    Re: Rand() function

    Quote Originally Posted by hypheni View Post
    1st of all use CODE tags around your code and 2nd thing is its a VC++ forum. Post all your further queries relates to C++ in this forum.

    And the solution is to use a 'static variable'. Though I didn't go through your code just posted the ans by reading the txt.
    There's no need for a static variable here. A local variable in the game function would suffice. He just needs to call rand outside of the guessing loop.

  7. #7
    Join Date
    Feb 2011
    Posts
    3

    Talking Re: Rand() function

    Thank you for your help GCDEF. I did what you said and it worked.

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