Thread: Generating Random Numbers

this is a example:

Code:

#include<cstdio>
#include<ctime>

main()
{
srand((unsigned)time(0));
//use time() function as seed of rand() function
int randomnum=rand()%1000;
//define a int,and initialize it to a 'random number'
// %1000 means this number wouldn't beyond 1000

}

The FAQ has a great tutorial on random numbers


essentially, what you will want to do.. is to use the rand() function.. which will return an unsigned random number ranging from zero to RAND_MAX (which is a very large number). Anywhoo.. use the modulus operator as an upper bound on the range of numbers you wish to use...

Code:

slot_output1 = rand()%5    //will return a random integer between 0 and 4

rand() may return a very large random number, but using the modulus operator will continously divide this larger number by 5 (in this example) until 5 is no longer able to fit into the randomly generated number.. and will return the remainder (if any)... and the remainder cannot be larger than 5

also, don't forget to seed your random number generator.. as per the faq.


edit: Hermitsky wins! (getting slow at me old age)

Here's the edit with random, still bad but should work. Why won't compile?

Code:

#include <iostream>
using namespace std;

int main()
{
    srand((unsigned)time(0));
    int return1=rand()%10;
    int return2=rand()%10;
    int return3=rand()%10;
    int coins=10;
    int input;
    
    cout << "Welcome to Slot Machine" << endl;
    cout << "You have 10 coins" << endl;
    cout << "Please press 1 to play, or 2 to exit and then hit enter";
    cin >> input;
    
    if(input==1)
    {
        cout << "You have chosen to play. Hit enter to input a coin and play";cin.get();
        cout << return1 << "   " << return2 << "   " << return3 << endl;
        if(return1==return2&&return1==return3)
        {
        coins=coins+10;
        cout << "You got the jackpot of 10 coins" << endl;
        cout << "You now have " << coins << " coins.";cin.get();
        cout << "Congratulations, you won.";
    }    
        else if(return1!=return2||return1!=return3||return2!=return3)
        {
        cout << "You lose";cin.get();
    }
    else
        {
        cout << "You have chosen to exit, please play again." << endl;   
    }    
        return 0;
}

the debugger says that there is a syntax error at line 39, a line that doesn't exist in my compiler, devc++

absolutly, you missed something,
this works fine:

Code:

#include <iostream>
#include <ctime>
#include <cstdlib>
using namespace std;

int main()
{
    srand((unsigned)time(0));
    int return1=rand()%10;
    int return2=rand()%10;
    int return3=rand()%10;
    int coins=10;
    int input;
    
    cout<<"Welcome to Slot Machine"<<endl;
    cout<<"You have 10 coins"<<endl;
    cout<<"Please press 1 to play, or 2 to exit and then hit enter"<<endl;
    cin>>input;
    
    if(input==1)
    {
        cout <<"You have chosen to play. Hit enter to input a coin and play"<<endl;
cin.get();
        cout <<return1<<"   "<<return2<<"   "<<return3<<endl;
        if(return1==return2&&return1==return3)
        {
        coins=coins+10;
        cout<<"You got the jackpot of 10 coins"<<endl;
        cout<<"You now have "<<coins<<" coins."<<endl;
cin.get();
        cout<<"Congratulations, you won."<<endl;;
    }    
        else if(return1!=return2||return1!=return3||return2!=return3)
        {
        cout <<"You lose, I am sillyI am sillyI am sillyI am sillyI am silly"<<endl;
    }
    else
        {
        cout<<"You have chosen to exit, please play again."<<endl;   
    }    
        return 0;
}
}

time() is defined in ctime,rand() is defined in cstdlib