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The random generator of INT and FLOAT

2010-08-12 00:39

In this example, I show some simple random generator examples using C++.

It simulates the generator of INT and FLOAT. The generator format is [a,b] or [a,b).

//////////////////////////////////////////////////////////////////////////
//
// Test the random generator of INT and float
//

#include <iostream>
#include <time.h>

void main()
{
    TestRandomIntFloatACM();
}

static void TestRandomIntClose(int ,int );
static void TestRandomFloatClose(float ,float);
static void TestRandomInt(int ,int );
static void TestRandomFloat(float ,float);
</pre>
<!--more-->
<pre class="brush: cpp; ruler:true ">//////////////////////////////////////////////////////////////////////////
//
//
//
void TestRandomIntFloatACM()
{
    // test the generator of INT
    TestRandomIntClose(1,10);
    TestRandomInt(1,10);

    // test the generator of FLOAT
    TestRandomFloatClose(1.0f,10.0f);
    TestRandomFloat(1.0f,10.0f);
}

//////////////////////////////////////////////////////////////////////////
//
// generate int [a,b)
//
void TestRandomInt(int a,int b)
{
    srand(unsigned(time(NULL)));

    std::cout &lt;&lt; "Generate int data [" &lt;&lt; a &lt;&lt; "," &lt;&lt; b &lt;&lt;")" &lt;&lt; std::endl;
    for(int i=0;i&lt;10;++i)
    {
        int generateInt = rand()%(b-a) + a;
        std::cout &lt;&lt; generateInt &lt;&lt; " " ;
    }
    std::cout &lt;&lt; std::endl;
}

//////////////////////////////////////////////////////////////////////////
//
// generate int [a,b]
//
void TestRandomIntClose(int a,int b)
{
    srand(unsigned(time(NULL)));

    std::cout &lt;&lt; "Generate int data [" &lt;&lt; a &lt;&lt; "," &lt;&lt; b &lt;&lt;"]" &lt;&lt; std::endl;
    for(int i=0;i&lt;10;++i)
    {
        int generateInt = rand()%(b-a+1) + a;
        std::cout &lt;&lt; generateInt &lt;&lt; " " ;
    }
    std::cout &lt;&lt; std::endl;
}

//////////////////////////////////////////////////////////////////////////
//
// generate float [a,b)
//
void TestRandomFloat(float a,float b )
{
    srand(unsigned(time(NULL)));

    std::cout &lt;&lt; "Generate float data [" &lt;&lt; (float)a &lt;&lt; "," &lt;&lt; (float)b &lt;&lt;")" &lt;&lt; std::endl;
    float range = b-a;
    for(int i=0;i&lt;10;++i)
    {
        double generateFloat = a + (range*rand()/(RAND_MAX+0.0));
        std::cout &lt;&lt; generateFloat &lt;&lt; std::endl ;
    }
    std::cout &lt;&lt; std::endl;
}

//////////////////////////////////////////////////////////////////////////
//
// generate float [a,b]
//
void TestRandomFloatClose(float a,float b )
{
    srand(unsigned(time(NULL)));

    std::cout &lt;&lt; "Generate float data [" &lt;&lt; (float)a &lt;&lt; "," &lt;&lt; (float)b &lt;&lt;"]" &lt;&lt; std::endl;
    float range = b-a;
    for(int i=0;i&lt;10;++i)
    {
        double generateFloat = a + (range*rand()/(RAND_MAX-1.0));
        std::cout &lt;&lt; generateFloat &lt;&lt; std::endl ;
    }
    std::cout &lt;&lt; std::endl;
}

Reference:

[1]. something about the function "rand()" :  http://wenku.baidu.com/view/34caf9c708a1284ac8504318.html