Pointer concatenation using function

Question

https://code.sololearn.com/ca3A24A4a3A1

Am I doing this right?
from the output why G is showing like double times after the function being called?

Answer 1

So in the end, the value of `ss` should be "ZZZZZZZZZZABCDEFG" right?

You can do this easily using the function strncpy() from the <string.h> header.
https://code.sololearn.com/cdk0zB5E4l7p/?ref=app

Answer 2

@Ipang
int m=len(ss)+len(s)+1
then char ss[m]
like this?
@XXX I have to do this according to the question otherwise I would have used string

Answer 3

Martin,
Thanks for telling, but honestly, it's confusing that they wrote "first n bytes" when they didn't mean to limit the number of copied bytes, but rather just copy the entire string.

Answer 4

The question is:
7.10
Write the following function that copies the first n bytes beginning with *s2 into the bytes
beginning at the location of the first occurrence of the null character’\0’ after *s1, where
n is the number of bytes that s2 has to be incremented before it points to the null character
'\0':
void cat(char* s1,const char* s2)

Answer 5

Your code appears to be changing contents of variable <s> accidentally.

I don't see any value of <n> in the code either. Shouldn't <n> be used to limit number of bytes copied over?

Answer 6

@Ipang what do you mean by<n>?

Answer 7

The task Description said:
"function that copies first n bytes ..."

That is what I mean by <n>. I thought your code was supposed to read a value of <n> to limit number of bytes to be copied.

Anyways, I've found the problem, you need to specify the size of variable <ss> to be at least (length-of-<ss>) + (length-of-<s>) + 1 for string terminator (null).

Answer 8

Ramisa,
It depends,

If you were allowed to statically specify size of <ss> directly, then just do like that `char ss[30]`

But if you're supposed to specify size of <ss> dynamically, then you'd take the `malloc()` and `free()` approach (C way), or `new` and `delete` approach (C++ way).

The task didn't clearly specify whether <ss> was to be a static or dynamic char array, so I'm not too sure.

Answer 9

Thank you

Answer 10

thank you @Martin

Answer 11

@Martin Thank you so much for elaborating