Diamond via string

#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
using namespace std;

int main(void) {
    int i, j, k, s, no;
    char sym = '#';
    no = 11;                  // pattern width = odd
    s  = (no /2) +1;          // mid-point

    string st;
    for (i=1;  i<s; ++i)      st.push_back(' ');
    int p = s-1;

    for (i=1;  i<s; ++i) {
        cout << st << sym;    reverse(st.begin(), st.end());
        cout << st << endl;   reverse(st.begin(), st.end());
        --p;
        st[p] = sym;
    }
        cout << st << sym;    reverse(st.begin(), st.end());
        cout << st << endl;   reverse(st.begin(), st.end());
        --p;

    for (i=1;  i<s; ++i) {
        cout << st << sym;    reverse(st.begin(), st.end());
        cout << st << endl;   reverse(st.begin(), st.end());
        ++p;
        st[p] = ' ';
    }
        cout << st << sym;    reverse(st.begin(), st.end());
        cout << st << endl;   reverse(st.begin(), st.end());
}