Serial Number C++ (Proof of Concept)

#include <stdlib.h>
#include <iostream>
char GetRandChar(){
    char temp = rand() % 36;
    return temp < 10 ? temp + '0' : temp - 10 + 'A';
}
void RandomizeString(char* randomizing, size_t size){
    for (int i = 0; i < size; i++){
        randomizing[i] = GetRandChar();
    }

}
int main(){
    char randstring[5];
    randstring[4] = 0;
    for (int i = 0; i < 4; i++){
        RandomizeString(randstring, 4);
        std::cout << randstring;
        if (i < 3) std::cout << "-";
    }
    system("PAUSE>NUL");
}