there is a for loop at the end of the function merge() wherin i<=num_elements is used. why is it <= and not just i< num_elements
#include<stdio.h>
void m_sort(int numbers[], int temp[], int left, int right);
void mergeSort(int numbers[], int temp[], int array_size);
void merge(int numbers[], int temp[], int left, int mid, int right);
void mergeSort(int numbers[], int temp[], int array_size)
{
m_sort(numbers, temp, 0, array_size - 1);
}
void m_sort(int numbers[], int temp[], int left, int right)
{
int mid;
if (right > left)
{
mid = (right + left) / 2;
m_sort(numbers, temp, left, mid);//this calls for sorting the left part
m_sort(numbers, temp, mid+1, right);//this calls for sorting the right part,mid+1 because mid goes to the left half in the previous statement
merge(numbers, temp, left, mid+1, right);//why mid+1
}
}
void merge(int numbers[], int temp[], int left, int mid, int right)//left middle and right of the array or left half or right half
{
int i, left_end, num_elements, tmp_pos;//num_elts for no._elts of array,l_e is middle postion,tmp_pos keeps track of the position of elt filling
//in the temporary array,i is used in for loop that comes in the end
left_end = mid - 1;//left end means the end of the left end
tmp_pos = left;//tmp pos is the postion of the place being filled in the temporary array
num_elements = right - left + 1;
while ((left <= left_end) && (mid <= right))//compares the first elts of the two halfs and fills it into temp array
{
if (numbers <= numbers[mid])
{
temp[tmp_pos] = numbers;
tmp_pos = tmp_pos + 1;
left = left +1;
}
else
{
temp[tmp_pos] = numbers[mid];
tmp_pos = tmp_pos + 1;
mid = mid + 1;
}
}
while (left <= left_end)//if right half used up fills the remaining slots in the temp array with the elts left in left half
{
temp[tmp_pos] = numbers;
left = left + 1;
tmp_pos = tmp_pos + 1;
}
while (mid <= right)//same as above while loop only thing is here the operation done on the other side
{
temp[tmp_pos] = numbers[mid];
mid = mid + 1;
tmp_pos = tmp_pos + 1;
}
for (i=0; i <= num_elements; i++)//copies the values from temp array to number array
{
numbers[right] = temp[right];
right = right - 1;
}
}
int main(void)
{
int size;
printf("enter the size of the array\n");
scanf("%d",&size);
int a[size],t[size];
printf("enter the elements\n");
for(int i=0;i<size;i++)
{
scanf("%d",&a[i]);
}
mergeSort(a,t,size);
for(int i=0;i<size;i++)
printf("%d ",a[i]);
return 0;
}