why the percentage of even and odd numbers generated by rand() is the same every time?

Question

I wrote this code to figure out how random is the rand() function, maybe there are other
ways to figure it out but i did what came to my mind first and with what knowledge i have
of c++, but turns out the percentage of even and odd number are 48-52 every time. i ran it with code::block IDE and it's the same every time. I thought the percentage of even and odd numbers would be also random.

please help me, what is it that i'm missing here??

#include <iostream>
#include <cstdlib>
using namespace std;

int main() {
int even = 0, odd = 0;
for(int i = 0; i < 100; i++){
int x = rand();
if(x%2==0){
even++;
}
else{
odd++;
}
}
cout << odd << " " << even ;
return 0;
}

Answer 1

Add srand(time(NULL)); before for loop and enjoy 💪👌

Answer 2

#include <random>

Answer 3

thank you for the answer Dejan Francuz.

code: https://code.sololearn.com/cFU9joCfp3HS/#cpp

Error:
..\Playground\: In function 'int main()':
..\Playground\:7:11: error: 'time' was not declared in this scope
srand(time(98));
^~~~
..\Playground\:7:11: note: suggested alternative: 'ftime'
srand(time(98));
^~~~
ftime

Answer 4

#include <time.h>

Answer 5

sorry didn't catch you're 2nd post,
here i figured something out: https://code.sololearn.com/cFU9joCfp3HS/#cpp
so it's truly random when i put different arguments in srand()
thanks for the help man.

Answer 6

MdChy nope, not really. Re-outputting that will give the exact same set of values because its dependent on a constant range of numbers. Just insert the correct libraries, cstdlib and ctime and use

srand(time(NULL));

which generates a seed dependent on the change of current time and date.