C++ Simple Stat Randomizer

#include <iostream>
#include <ctime>

void hp(int base);
void attack(int base);
void defense(int base);
void speed(int base);

int main(){
    //Assignment: Create a unique function.
    //Challenge: Calculate stats in other functions and return them.
    srand(time(0));
    int base_stat = 0;

    do{
    std::cout << "Enter in a base stat (0-50): ";
    std::cin >> base_stat;
    if(base_stat > 50 || base_stat <= 0){
        std::cout << "Stat not in range! ";
        base_stat = 0;
    }
    }while (base_stat == 0);

    std::cout << "Stats\n";
    hp(base_stat);
    attack(base_stat);
    defense(base_stat);
    speed(base_stat);

    return 0;

}

void hp(int base){
    base;
    int hp = rand() % 11 + base + 30;
    std::cout << "HP: " << hp << '\n';
}

void attack(int base){
    base;
    int attack = rand() % 11 + base;
    std::cout << "Attack: " << attack << '\n';
}

void defense(int base){
    base;
    int defense = rand() % 11 + base;
    std::cout << "Defense: " << defense << '\n';
}

void speed(int base){
    base;
    int speed = rand() % 11 + base;
    std::cout << "Speed: " << speed << '\n';
}