Thread: Random Number Generator?

rand() gives a random integer between 0 and RAND_MAX. Use modulus (a % b) on the result to cut it into your desired interval.

Code:

int number = rand() % 10 + 1;

Or as a more general function:

Code:

int RandomInt(int Min, int Max)
{
	if(Max <= Min) return Min;

	return Min + rand() % (Max - Min + 1);
}

int number = RandomInt(1, 10);

Thanks, that seems to have been what I needed. However, now I seem to be having compiler problems. I have done everything as I should have, but my Dev C++ Compiler is unable to compile my program.

Here is the code:

Code:

#include <stdio.h>
#include <iostream.h>

int main(int nNumberofArgs, char* pszArgs[])
{
    int guess;
    cout << "I'm thinking of a number between 1 and 10."
    cout << "\nGuess what it is."
    cin >> guess;
    int number = rand() % 10 + 1;
    if (guess==number)
        {
        cout << "Correct!"
        }
    else
        {
        cout << "Wrong."
        }
    return 0;
}

Is the stuff after int main, or the if statement? Or could it be my compiler (Dev C++)????

You are missing quite a few semicolons in your code. Plus you are using the old style headers.

Code:

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

int main(int nNumberofArgs, char* pszArgs[])
{
    int guess;
    cout << "I'm thinking of a number between 1 and 10.";
    cout << "\nGuess what it is.";
    cin >> guess;
    int number = rand() % 10 + 1;
    if (guess==number)
        {
        cout << "Correct!";
        }
    else
        {
        cout << "Wrong.";
        }
    return 0;
}

I've never had that error before, but I googled your error and came up with this FAQ entry:
http://aditsu.freeunixhost.com/dev-cpp-faq.html#runfile

I tried all of that and it still doesn't work... This is starting to get annoying...

EDIT: Now it compiles the program but doesn't create an exe. This is getting frustrating.

Post your compile log, which can be accessed via the tab of the same name towards the bottom.

You should be using Dev-C++ 4.9.9.x, the most recent version is 4.9.9.2

alright I written one wich works PERFECTLY in my dev-C++
it it doesn;t work you should re-install your dev-C++ compiler.

Code:

#include <iostream>

using namespace std; // using standard libary //

int main ( int argc , char** argv ) 

{ 
    srand(time(0));
int random_number = rand() % 10 ;// not larger than 10 //
cout << random_number << endl; //out puts it //
cin.ignore(); // waits for an input and ignores it //
}

cin.get() works.
Or if you want to use the evil system("pause"), go right ahead. system() is defined in stdlib.h or cstdlib.

And no....C++ hasn't changed a lot recently. If you don't understand his example code, you really need to go back to some beginner tutorials dear. If you're confused about the parameters of main(), don't worry...they're not even used in the example.

@Myst Wind: it should be:

Code:

 int random_number = rand() % 11;

Originally Posted by Krak

@Myst Wind: it should be:

Code:

 int random_number = rand() % 11;

That would give a number 0 -> 10, he wanted 1 -> 10.