Srand function not working and rand function giving same random integ

Question

0.00/5 (No votes)

See more:

In my code srand is not working and i am getting same integar value every time loop runs.

What I have tried:

#include <iostream>
#include <ctime>
#include <cstdlib>
using namespace std;
int main()
{
	string n;
	int len;
	int a,sum;
	int x[100];
//	cout <<"Enter credit card numbers\n";
//	cin>>n;
	for(int h=0; h<16;h++)
	{
		
  	srand(time(0));
  	x[h] = rand()%10;

	}
//	len=n.length();
for(int k=0; k<16; k++)
	{
		cout<<x[k]<<",";
	}
//		cout <<"Number is "<<n;
	cout <<endl;
}

Posted 22-Jan-22 22:33pm

Hamza Jameel

Updated 22-Jan-22 22:43pm

Add a Solution

1 solution

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

OriginalGriff · Accepted Answer · 2022-01-22T22:43:00

The problem is that modern processors are too fast for your code:

for(int h=0; h<16;h++)
	{
		
  	srand(time(0));
  	x[h] = rand()%10;

	}

Because they are fast, the calls to time(0) are all occurring in the same second, so the value passed to srand to initialize the random number generator is always the same, and it gets reset to the same sequence. So every time round the loop, you get the same random number (though a different number each time you run your program).

Move the call to srand outside the loop completely so the random number generator is only initialized once, and you will get different values when you call rand