Example: Print Star Pattern without using loop in C++

#include <bits/stdc++.h>

#include <cmath>

using namespace std;

​

int i = 1, r = 1;

​

// It's the recursive function

// to print the star pattern

void starPattern(int n) {

    ((int) sqrt(pow((i - (2 * n - 1) *(r - 1) - n), 2)) < r) ? cout << "*" : cout << " ";

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    if ((i - (2 * n - 1) * (r - 1)) % (2 * n - 1) == 0) {

        cout << "\n";

        r++;

    }

​

    if (i++ < n * (2 * n - 1))

        starPattern(n);

}

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// It's the driver function

int main() {

    // size of the pattern

    int x;

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    cout << "-----Enter the size of the pattern-----\n";

    cin >> x;

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    // This will print the pattern

    starPattern(x);

    return 0;

}