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:

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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;
}

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

How big can n be?

Your code leaks memory all over the place.

Quote:

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Originally Posted by Salem

How big can n be?

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

Quote:

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Originally Posted by Salem

Your code leaks memory all over the place.

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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

Quote:

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Originally Posted by gawiellus

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

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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:

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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

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temp is the one leaking memory since you don't free it before the function ends.
However, it's pointless for it to be dynamic anyway.

For n = 65536, result must be 10,687,148,122 bytes.

If you just have to print it, why are you making a string?
Why not just

Code:

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for (int i = 1; i <=n; ++i) {
    for (int j = 0; j < n; ++j)
        printf("%d", i);
    putchar('\n');
}

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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.

Code:

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#include <stdio.h>

int printPattern(int n) {
    for (int i = 0; i < n; i++) {
        printf("%i",n);
    }
}

void numberTree(int n) {
    for (int i = 1; i < (n+1); i++) {
        printPattern(i);
        printf("\n");
    }
}

int main() {
    numberTree( 9 );
    return 0;
}

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