/* rand.cpp
 *
 * Test generation/limits of random numbers.
 * Writes information to standard output (cout)
 * and two different files (test3.out and test4.out).
 *
 * Bruce M. Bolden
 * October 9, 1997
 * -------------------------------------------------
 */

#include <iostream.h>
#include <fstream.h>
#include <iomanip.h>
#include <stdlib.h>
#include <time.h>

    //  prototypes
void Test1( int n );
void Test2( int n, int rMax );
void Test3( ofstream& fOut, int n );
void Test4( int n, double rMin, double rMax );


main()
{
    cout << "Random Number Testing\n\n" << endl;

        //  What is RAND_MAX?  32,767 using g++
    cout << "RAND_MAX: " << RAND_MAX << endl;

    //  Random number generator can be seeded with current time 
    //  so that the numbers will be different every time the 
    //  program is run.  
    //  Be careful:  This can make testing difficult.
   
    srand( (unsigned)time( NULL ) );

    cout << "\nRandom numbers (full range)\n" << endl;
    Test1( 10 );       //  Generate 10 random numbers

    cout << "\nRandom numbers (0..100)\n" << endl;
    Test2( 10, 100 ); 

    ofstream fOut( "test3.out", ios::out );
    fOut << "\nRandom number distribution (0..5)\n" << endl;
    if( !fOut )
    {
        cerr << "Unable to open \"test3.out\"" << endl;
    }
    else
    {
        for( int i = 0 ; i < 20 ; ++i )
        {
            Test3( fOut, 600 );
        }
        fOut.close();
    }

    cout << "\nRandom numbers (5.0..10.0)\n" << endl;
    Test4( 50, 5.0, 10.0 );
}


/*  Test1
 *  Generate n random numbers.
 */

void Test1( int n )
{
    for( int i = 0 ; i < n ; i++ )
    {
        //printf( "  %6d\n", rand() );
        cout << "  " << setw(6) << rand() << endl;
    }
}


/*  Test2
 *  Generate n random numbers within the specified
 *  range:  0..rMax
 */

void Test2( int n, int rMax )
{
    rMax++;

    for( int i = 0 ; i < n ; i++ )
    {
        cout << "  " << setw(6) << (rand() % rMax) << endl;
    }
}


/*  Test3
 *  Generate n random numbers within the specified
 *  range:  0..5 and tabulate them.
 */

void Test3( ofstream& fOut, int n )
{
        //  Save the test number between usages by
        //  declaring testNumber to be static.
    static int testNumber = 1;

    int n0 = 0;   //  counters---array would be better!
    int n1 = 0;
    int n2 = 0;
    int n3 = 0;
    int n4 = 0;
    int n5 = 0;

    for( int i = 0 ; i < n ; i++ )
    {
        int iRand = (rand() % 6);

        switch( iRand )
        {
        case 0:
            n0++;
            break;
        case 1:
            n1++;
            break;
        case 2:
            n2++;
            break;
        case 3:
            n3++;
            break;
        case 4:
            n4++;
            break;
        case 5:
            n5++;
            break;
        default:
            cerr << "Error generating random number!" << endl;
        }
    }
        //  show results
    fOut << "\nTest #" << testNumber++ << endl;

    fOut << " 0: " << setw(5) << n0 << endl;
    fOut << " 1: " << setw(5) << n1 << endl;
    fOut << " 2: " << setw(5) << n2 << endl;
    fOut << " 3: " << setw(5) << n3 << endl;
    fOut << " 4: " << setw(5) << n4 << endl;
    fOut << " 5: " << setw(5) << n5 << endl;
}

/*  Test4
 *  Generate n random numbers within the specified
 *  range:  rMin..rMax
 *  Note:  rMin and rMax are real numbers.
 */

void Test4( int n, double rMin, double rMax )
{
    double rVal;      //  random value
    double range = rMax - rMin + 1.0;

    ofstream fOut( "test4.out", ios::out );

    for( int i = 0 ; i < n ; i++ )
    {
        //  move range calculation outside loop!
        //rVal = rMin + double(rand() % int(rMax-rMin+1.0));
        rVal = rMin + double(rand() % int(range));

        //cout << "  " << setw(6) << rVal << endl;
        fOut << "  " << setw(6) << rVal << endl;
    }

    fOut.close();
}