Thread: Returning pattern

Hi
I am writing programm to print pattern like below
1
22
333
4444
55555
666666
up to n given as a parametr.
my code below

Code:

char* pattern(const int n)
{
	char *result = (char*)malloc(sizeof(char)*n*n*n*n);
	char *temp = (char*)malloc(sizeof(char) * 4);
	memset(result, '\0', (n*n*n*n));
	if (n<1)
		return "";
	for (int i = 1; i <= n; i++)
	{
		for (int j = 1; j <= i; j++)
		{
			sprintf(temp, "%d", i);
			strcat(result, temp);
		}
		strcat(result, "\n");
	}
	result[strlen(result) - 1] = '\0';
	return result;
}

I pass all basic test but on random test i got some errors. Can you tell me where is mistake

Originally Posted by Salem

How big can n be?

maximum n size is 2^16 which give us 65 536 so n should be at least 5 characters long

Originally Posted by Salem

Your code leaks memory all over the place.

I thought that I don't have to calculate perfect value of characters for each n thats why I allocated bigger memory than I need

Originally Posted by gawiellus

maximum n size is 2^16 which give us 65 536 so n should be at least 5 characters long

Then, it is not possible with your code... result will have to point to a buffer which requires 2^64 bytes ( 1 EiB ).

This is task from codewars site so probably n is correct value.
So the way is to calculate perfect bytes of allocated memory? For example

Code:

if(n<9)
 size=n*(n+1)/2;
if(n>9&&n<=99)
size=2*(n*(n+1)/2)+(n+1)/2
if(n>99&&n<=999)
size=3*(n*(n+1/2)+2*(n*(n+1)/2)+(n+1)/2

Sorry I probably said wrong my task is not print but return as a string. If memory is limited than probably n must be lower than 65536. As I said this is task from codewars site then n must be correct value.