How do I get two different random numbers in the same srand() seed? C++

I am trying to create a random password generator. When I call the function multiple times it returns the same character value. QQpQ;7Q7pQ;p

I have tried adding srand(time(0)); or srand((unsigned int) time(NULL)); in my main function.

Looking at other stack over flow posts I see that srand helps create different characters each time I run the program. However it still returns multiples of the same character.

How can I change srand() seed during run time to get different random numbers?

#include <string>
#include <iostream>
#include <time.h>

using namespace std;

string randomGenerator(int numberOfCharacters);
char randomCapitalCharacter();
char randomLowerCharacter();
char randomSpecialCharacter();
char randomInt();

int main(){
    srand((unsigned int) time(NULL));
    int passwordLength = 12;
    string password = randomGenerator(passwordLength);
    cout << password << endl;
    return 0;
}

string randomGenerator(int numberOfCharacters){
    char randomCharacterTypes[4] = {randomLowerCharacter(),randomInt(), randomCapitalCharacter(), randomSpecialCharacter()};
    std::string password;

    while (numberOfCharacters > 0){
        int random = rand()%4;
        password += randomCharacterTypes[random];
        numberOfCharacters--;
    }
    return password;
}
char randomInt(){
    std::string numberAsString = to_string(std::rand()% 10);
    char randomNumberChar = numberAsString.at(0);
    return randomNumberChar;
}
char randomLowerCharacter(){
    return 97 + rand()%26; //97 = a
}
char randomCapitalCharacter(){
    return 65 + rand()%26; //65 = A
}
char randomSpecialCharacter(){
    /** Special characters are split by numbers so we pick a random from one of the 2 groups.*/
    return (rand()%2) ? char(33 + rand()%14) : char(58 + rand()%8); 
}

• srand() — why call it only once?
• Why does rand() yield the same sequence of numbers on every run?