Insertion Sort Variation - c++

Question

#include <iostream>
using namespace std;
void print_array(int array[], int size)
{
cout<< "insertion sort steps: ";
int j;
for (j=0; j<size;j++)
cout <<" "<< array[j];
cout << endl;
}
void insertion_sort(int a[], int n)
{
int i;
for(int j = 1; j < n; j++) {
i = 0;
while ((a[j] > a[i])) {
i = i+1;
}
int m = a[j];
for(int k = 0; k <= (j-i-1); k++) {
a[j-k] = a[j-k-1];
}
a[i] = m;
print_array(a,n);
}
}
int main() {
int array[6]= {3,2,4,5,1,6};
insertion_sort(array,6);
return 0;
}
I am trying to modify this the insertion sort that it uses a linear search technique that inserts the jth element in the correct place by first comparing it with the (j − 1)st element, then the (j − 2)th element if necessary, and so on.
So where it says i = 0; it should now be i = j-1;
My attempt:
void insertion_sort(int a[], int n)
{
int i;
for(int j = 1; j < n; j++) {
i = j-1;
while ((a[j] > a[i]) && (i > 0)) {
i = i-1;
}
int m = a[j];
for(int k = (j-i-1); k >= 0; k--) {
a[j-k] = a[j-k-1];
}
a[i] = m;
print_array(a,n);
}
}
Here is the output
insertion sort steps: 2 3 4 5 1 6
insertion sort steps: 4 2 2 5 1 6
insertion sort steps: 5 4 4 4 1 6
insertion sort steps: 5 4 4 1 4 6
insertion sort steps: 6 5 5 5 5 5
The first step is works correct by the 2nd step is when it all starts to fail.

Answer 1

The
while ((a[j] > a[i]) && (i > 0)) {
i = i-1;
}
is wrong, because it causes insertion of a[j] at index 0 if a[j] were not to be moved. Change that to
while (0 <= i && a[j] < a[i]) --i;
++i;
Also, the shifting loop is wrong and complicated - change it to
int m = a[j];
for (int k = j; k > i; k--) a[k] = a[k-1];
a[i] = m;