What i want to do if i havd to generate random number between 20-100?

Answer 1

Umm something like...

#include <iostream>

#include<cstdlib>
#include<ctime>

using namespace std;

int main() {

int x;
srand(time(0));
x=(1+(rand()%100));
if(x<20)
x=x+20;
cout<<x;

return 0;
}

Answer 2

http://www.cplusplus.com/reference/random/

Answer 3

v = rand() % 100 + 20;