Random number generator in c programming

This tutorial contains

• How to generate a random number using rand()
• Simple example using rand() function
• Generate random number in a specific range dice example

To generate a random number in c++ program first we have to include a header file which is
#include<cstdlib> because we have to use a function from that library which is “rand();” this functions simple returns a random number

Let use that function

#include<iostream> #include<cstdlib> using namespace std; int main(){   cout<<rand()<<endl; return 0; }

It will return a random number for example
41
 Let use a loop and generate some more random numbers using that function

#include<iostream> #include<cstdlib> using namespace std; int main(){  for(int i=1;i<=10;i++)     cout<<rand()<<endl; return 0; }

It will generate 10 random  numbers
What if we want to generate random numbers with in the specific range like we want to generate random numbers between 1 to 10 or 50 to 100

for example range is 1 to 10

We think something like that cout<<rand()%10;

How it will work

It will take a random number divide it by 10 and return us the number the number can be from 0 to 9
After getting the output we see that if we add 1 in the result value we can get our required range values

So we will change it like that << 1 + ( rand() % 10 ) ;

Lets take another example of a dice it can generate numbers 1 to 6 randomly

 we will simple something like that
But is it write or not

for(int i=1;i<=6;i++)     cout<< rand()%6<<endl;

And there is a problem it will return us number from 0 to 5 to make the logic of our program we will change it like that

for(int i=1;i<=6;i++)     cout<< 1+ (rand()%6)<<endl;

So this will work fine in this case 0 is eliminate and whatever number will return 1 will be added in it like if 0 is generated it will result as 1 if 5 is generated it will return us 6
  
Hope this tutorial will help to understand the basic about of random number

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