C++ LANGUAGE RANDOM NUMBERS PAGE 78

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C++ LANGUAGE RANDOM NUMBERS

Random Numbers in C++ 


There are many cases where you will wish to generate a 
random number. There are actually two functions you will 
need to know about random number generation. The first is 
rand(), this function will only return a pseudo random number. 
The way to fix this is to first call the srand() function. 

Following is a simple example to generate few random numbers. 
This example makes use of time() function to get the number of 
seconds on your system time, to randomly seed the rand() function: 

#include <iostream> 

#include <ctime> 

#include <cstdlib> 
 
using namespace std; 
  
int main () 
{ 
   int i,j; 
  
   // set the seed 
   srand( (unsigned)time( NULL ) ); 
 
   /* generate 10  random numbers. */ 
   for( i = 0; i < 10; i++ ) 
   { 
      // generate actual random number 
      j= rand(); 
      cout <<" Random Number : " << j << endl; 
   } 
 
   return 0; 
} 
When the above code is compiled and executed, it produces the following result: 
 Random Number : 1748144778 
 Random Number : 630873888 
 Random Number : 2134540646 
 Random Number : 219404170 
 Random Number : 902129458 
 Random Number : 920445370 
 Random Number : 1319072661 
 Random Number : 257938873 
 Random Number : 1256201101 
 Random Number : 580322989