Given an array of integers, {1,0,2,0,3,0,0,4,5,6,7,0,0,0}, you have to create a new array which will be like (1,2,3,4,5,6,7,0,0,0,0,0,0,0}, without using any other temporary array.

From: here.

-- solution --


#include <iostream>
using namespace std;

// This works.
void sep(int A[], int n) {
    if (n <= 1) return;
    int k = 0; // pos of non-zero
    for (int i = 0; i < n; ++ i) {
        if (A[i] != 0) {
            A[k] = A[i];
            if (k != i) A[i] = 0;
            ++ k;
        }
    }
}


void dump(int A[], int n) {
    for (int i = 0; i < n; ++ i) {
        if (i > 0) cout << ", ";
        cout << A[i];
    }
    cout << endl;
}


int main() {
    int A[] = {1,0,2,0,3,0,0,4,5,6,7,0,0,0};
    int n = sizeof(A) / sizeof(int);

    dump(A, n);
    sep(A, n);
    dump(A, n);
}