C language: random generated number + merge sort

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <assert.h> 
#define MAXSIZE 10
void initArr(int arr[] , int length);
void showArr(int arr[] , int length);
void merge(int arr[],int low,int mid,int height,int *temp);
void merge_sort(int arr[],int low,int height,int *temp);
void mergeSort(int arr[],int length);
int main()
{
    
	srand((unsigned int)time(NULL));
	int arr[MAXSIZE];
	printf("========== The sequence before sorting =============\n");
	initArr(arr,MAXSIZE);
	showArr(arr,MAXSIZE);
	printf("========== Sequence after merging and sorting =============\n");
	mergeSort(arr,MAXSIZE);
	showArr(arr,MAXSIZE);
	system("pause");
	return 0;
} 
void initArr(int arr[] , int length)
{
    
	for(int i = 0 ; i < length ; i++){
    
		arr[i] = rand()%20;
	}
}
void showArr(int arr[] , int length)
{
    
	for(int i = 0 ; i < length ; i++){
    
		printf("%4d",arr[i]);
	}
	printf("\n");
} 
void merge(int arr[],int low,int mid,int height,int *temp)
{
    
	int i = low;
	int j = mid+1;
	int k = low;
	while(i <= mid && j <= height){
    
		temp[k++] = arr[i]<arr[j]?arr[i++]:arr[j++];
	}
	while(i <= mid){
    
		temp[k++] = arr[i++];
	}
	while(j <= height){
    
		temp[k++] = arr[j++];
	}
	for(i = low ; i <= height ; i++){
    
		arr[i] = temp[i];
	}
}
void merge_sort(int arr[],int low,int height,int *temp)
{
    
	if(low>=height){
    
		return;
	}
	int mid = low + (height - low)/2;
	merge_sort(arr,low,mid,temp);
	merge_sort(arr,mid+1,height,temp);
	merge(arr,low,mid,height,temp);
}
void mergeSort(int arr[],int length)
{
    
	int *temp = (int *)malloc(sizeof(int)*length);
	assert(temp);
	merge_sort(arr,0,length-1,temp);
	free(temp);
}