Quick Sort

# include <iostream>
using namespace std;

int n, arr[100];

void swap_int( int *a, int *b ) {
    int temp = *a;
    *a = *b;
    *b = temp;
}

void q_sort(int f, int l) {
    if( f>=l ) return;

    int i=f+1, j=l;

    do {
        while( arr[i]<arr[f] ) i++;
        while( arr[j]>arr[f] ) j--;
        if( i<j ) swap_int( &arr[i], &arr[j] );
    } while( i<j );

    swap_int( &arr[f], &arr[j] );

    q_sort( f, j-1 );
    q_sort( j+1, l );
}

int main() {
    cin>>n;
    for( int i=0; i<n; i++ ) cin>>arr[i];

    q_sort(0,n-1);

    for( int i=0; i<n; i++ ) cout << arr[i] << " "; cout << endl;

    return 0;
}