Sorting method and computation time

[SteroidalPsycho]

This is my assignment:
Write a merge sort function. Test it with 100,000 numbers (I'm only using 100 right now). Print the time used to complete the sorting. Execute the functions of selection or bubble sorts (use the code presented in slides for selection and bubble sort) and compare the time used.

Now, I have written the code below but it is throwing an error when I run it that says: Run-Time Check Failure #2 - Stack around the variable 'c' was corrupted.
I can't figure out what is wrong with the code below. Please help! Much appreciated!

#include <iostream>
#include <time.h>

using namespace std;
void mergesort(int[], int, int);
void merge(int[], int, int, int);
void mergesort(int a[], int low, int high)
{
int mid;
if(low<high)
{
mid=(low+high)/2;
mergesort(a,low,mid);
mergesort(a,mid+1,high);
merge(a,low,high,mid);
}

}

void merge(int a[], int low, int high, int mid)
{
int i, j, k, c[50];
i=low;
j=mid+1;
k=low;
while((i<=mid)&&(j<=high))
{
if(a[i]<a[j])
{
c[k]=a[i];
k++;
i++;
}
else
{
c[k]=a[j];
k++;
j++;
}
}
while(i<=mid)
{
c[k]=a[i];
k++;
i++;
}
while(j<=high)
{
c[k]=a[j];
k++;
j++;
}
for(i=low;i<k;i++)
{
a[i]=c[i];
}
}

int main ()
{
	int randNum[100]; 
	clock_t sTime;
	srand((unsigned)clock()); 

	cout << "Start generating random numbers..." << endl;
	for(int index=0; index<100; index++){ 
		randNum[index] = (rand()%1000)+1; 
	}
	
	sTime = clock();
	mergesort(randNum, 0, 99);
    // delay the program by 0.05 second
    clock_t cWait = clock();

	cout << "Total CPU time used: " << (double) (clock()-sTime)/CLOCKS_PER_SEC \
    << " seconds" << endl; 
}

[SteroidalPsycho]

Nevermind lol. I figured out what was wrong. In line 22 i had c[50] instead of 100.