Question

I am reading “Introduction to Algorithms” and read about the insertion sort.
I tried to implement it myself without first reading their solution.

Here is my solution, is this insertion sort?

#include <iostream>

using namespace std;

int main()
{
    // initialize an unsorted array
    int a[] = {5,6,4,7,3,8,2,9,0,1};

    // define variables
    int i,j,tmp;

    for (int j=1; j<10; ++j)
    {
        for (int i=0;i<j;++i)
        {
            if (a[j] < a[i])
            {
                tmp = a[j];
                a[j] = a[i];
                a[i] = tmp;
            }
        }

    }

    for (i=0;i<10;++i)
    {
        cout << a[i] << endl;
    }

    return 0;
}

Ok, I’ve read it, and understand why it wasn’t insertion sort… this is much better.

   #include <iostream>

    using namespace std;

    int main()
    {
        // initialize an unsorted array
        int a[] = {5,6,4,7,3,8,2,9,0,1};

        // define variables
        int i,j,key,c;

        for (int j=1; j<10; ++j)
        {
            key = a[j];
            i = j - 1;

            while(i>=0 && a[i] > key)
            {
                a[i+1] = a[i];
                i = i - 1;
            }
            a[i+1] 

= key;
        ++c;
    }

    for (i=0;i<10;++i)
    {
        cout << a[i] << endl;
    }

    cout << endl << c << endl;
    return 0;
}

Answer 1

Your solution seems to be bubble sort, not insertion sort.