Making stairs and a bow tie

stairbowtie.cpp

#include <iostream>
using namespace std;

void makeBowTie(int h) {
    int i, j, k, s;
    for (i = 1; i <= h; ++i) {
        s = 2*i-1;
        s = h - abs(h - s);
        for (j = 0; j < s; ++j) cout << '*';
        for (j = 0; j < 2*h - 2*s; ++j) cout << ' ';
        for (j = 0; j < s; ++j) cout << '*';
        cout << '\n';
    }
}

void makeStairs(int h) {
    int i, j, r = h/2+1;
    for (i = 1; i <= h; ++i) {
        int s = r - abs(r - i);
        for (j = 0; j < s; ++j) cout << '*';
        cout << '\n';
    }
}

void StairCase(int h) {
  for (int i = h; i >= 1; --i) {
    for (int j = 1; j < i; ++j) cout << ' ';
    for (int k = i; k <= h; ++k) cout << '#';
    cout << '\n';
  }
}

int main(){
    makeBowTie(5);
    cout << '\n';
    makeStairs(5);
}

How was I able to come up with this code! I thought I wasn't good at math....