C++ guessing game problem with random numbers

Question

Whenever a number is given as an input, it always say too low even if I put negative value while the less and max random number is 1-100. I don't really understand why it is not working.

#include<iostream>

Is there a problem in here?

#include<cstdlib>
#include<time.h>

above

using namespace std;
void again();
void play_game();
void again()
{
    int schoice;
    while(true)
    {
        cout<<"\n\nYou want to play again?\n\n";
        cout<<"1) Play Again"<<endl;
        cout<<"0) Exit\n\n";
        cout<<"Input answer:";
        cin>>schoice;
        if(schoice == 1)
        {
            play_game();
        }
        else if(schoice == 0)
        {
            cout<<"\nOh ok see ya!\n\n";
            break;
        }
    }
}
void play_game()
{

Or the problem is in here?

    srand(time(0));
    int RanNum;
    RanNum = rand() % 100 + 1;

This part I don't really understand (above)

    cout<<"\n\n*The game is being played*\n\n"<<endl;
    cout<<"Guess the number between 1 to 100\n"<<endl;
    while(true)
    {
        cout<<"Input number:";
        int maxNum = 100;
        int leastNum = 1;
        int guess;
        cin>>guess;
        if(guess < leastNum || guess > maxNum)
        {
            cout<<"It must be higher or equal than"<<" "<<leastNum<<endl<<"and it must not exceed"<<" "<<maxNum<<endl;
        }
        else if(guess < RanNum)
        {
            cout<<"\nYour number is LOW\n"<<endl;
        }
        else if(guess > RanNum)
        {
            cout<<"\nYour number is HIGH\n"<<endl;
        }
        else
        {
            cout<<"\nYour correct!";
            again();
            break;
        }
    }
}
int main()
{
    int choice;
    cout<<"Want to play the game?\n\n"<<endl;
    cout<<"Type 1 if want to play"<<endl<<"Type 0 if not\n\n"<<endl;
    cout<<"Input here:";
    cin>>choice;
    switch(choice)
    {
    case 1 :
        play_game();
        break;
    case 0 :
        cout<<"\nOh ok see ya!\n\n";
        break;
    default :
        cout<<"\n\nThe choices are\n\n1 or 0 \n\nplease try again\n\n";
        break;
    }
    return 0;
}