I am a C begginer I was trying to code a merge_sort function. I wrote my code below.
variable "array_global" is the merge between array "a" and array "b", and all that merge proccess works fine, the problem occurs when the function returns "array global", since it seems that it only returns the first element of the array.
For example, if "array_global" is [19, 26], integer pointer "a" which receives the result of the function only receives [19]
What did I did wrong? And why this happens?
Thx in advance
int *merge_sort(int array[], int len)
{
if (len == 1)
{
return array;
}
else
{
int l1 = (len/2);
int l2 = len - l1;
int sub_array_1[l1]; int sub_array_2[l2];
for (int i = 0; i<l1; i )
{
sub_array_1[i] = array[i];
}
for (int i = l1; i<len; i )
{
sub_array_2[i-l1] = array[i];
}
int *a = merge_sort(sub_array_1, l1);//Receives array_global value
int a_size = (sizeof(a)/sizeof(int));
int *b = merge_sort(sub_array_2, l2);//Receives array_global value
int b_size = (sizeof(b)/sizeof(int));
int mult = a_size b_size;
int *array_global = malloc(sizeof(*array_global)*mult);
merge(a, b, a_size, b_size, array_global);
return array_global;
}
}
CodePudding user response:
Mistake here:
int a_size = (sizeof(a)/sizeof(int));
should read
int a_size = l1;
sizeof
doesn't measure the size of an array on the heap.
Memory leak here:
return array_global;
should be:
free(a);
free(b);
return array_global;