Wrong output from insertion sort - c

Question

I get the wrong output when I execute my program, and I have no clue to what might be causing it.
As you can se below I have an array. However when executing the program I get the output:
array[0]=3
array[1]=1
array[2]=1
array[3]=5
array[4]=5
array[5]=8
Obviously it's not my expected output which would be {1,3,4,5,7,8}. What am I doing wrong?
#include <stdio.h>
#include <stdlib.h>
#define l 6
void isnertionSort(int array[]);
int main(void)
{
int array[l]={3,4,1,7,5,8};
for(int i=0; i<l;i++) {
printf("array[%d]=%d\n", i, array[i]);
}
printf("\n");
isnertionSort(array);
for(int i=0; i<l; i++){
printf("array[%d]=%d\n", i, array[i]);
}
return 0;
}
void isnertionSort(int array[])
{
int j,key;
for(int i =1;i<l;i++){
key = array[i];
j = i -1;
while(j>0 && array[j]>key){
array[j+1]=array[i];
j--;//j=j-1
}
array[j+1]= key;
}
}

Answer 1

Your inner loop has two minor bugs.
while(j >= 0 && array[j]>key) { /* j> 0 changed to j>=0 */
array[j+1]=array[j]; /* changed from i to j */
j--;
}
It's fairly straight-forward to debug if you compare your implementation with insertion sort algorithm. It would also help if you indent your code so that these sort of bugs can be spotted more easily.

Answer 2

For starters neither declaration from the header <stdlib.h> is used in the program. So the directive
#include <stdlib.h>
may be removed.
It is much better to use capital letters for #defined names. For example
#define N 6
It is difficult to distinguish low case letter l and 1 for the reader of the code.
You should write a general sorting function instead of a function that can accept arrays with only fixed 6 elements. So the function should be declared with two parameters as for example
void isnertionSort( int array[], size_t n );
This loop
while(j>0 && array[j]>key){
array[j+1]=array[i];
j--;//j=j-1
}
1) does not touch the elements of the array with the index equal to 0 and 1 and 2) sets all elements that are greater than key to key because key and array[i] are the same value.
array[j+1]=array[i];
^^^^^^^^
Taking all this into account the program can look the following way
#include <stdio.h>
#define N 6
void isnertionSort( int array[], size_t n );
int main(void)
{
int array[N] ={ 3, 4, 1, 7, 5, 8 };
for ( size_t i = 0; i < N; i++ )
{
printf( "array[%zu] = %d\n", i, array[i] );
}
putchar( '\n' );
isnertionSort( array, N );
for ( size_t i = 0; i < N; i++ )
{
printf( "array[%zu] = %d\n", i, array[i] );
}
putchar( '\n' );
return 0;
}
void isnertionSort( int array[], size_t n )
{
for( size_t i = 1; i < n; i++ )
{
size_t j = i;
int value = array[i];
for ( ; j != 0 && value < array[j-1]; --j )
{
array[j] = array[j-1];
}
if ( j != i ) array[j] = value;
}
}
The program output is
array[0] = 3
array[1] = 4
array[2] = 1
array[3] = 7
array[4] = 5
array[5] = 8
array[0] = 1
array[1] = 3
array[2] = 4
array[3] = 5
array[4] = 7
array[5] = 8