CODEWITHSUNDEEP
c++
Zelkop
Zelkop

Reputation: 109

Pointer value to array C++

I'm trying to set a pointer array to a char array in class Tran, however it only applies the first letter of the string. I've tried many other ways but can't get the whole string to go into name.

edit: name is a private variable

char name[MAX_NAME + 1];

Trying to output it using cout << name << endl;

the input is:

  setTran("Birth Tran", 1);

help would be appreciated, thank youu

Upvotes: 0

Views: 62

Answers (2)

ExaltedBagel
ExaltedBagel

Reputation: 667

The underlying issue you are trying to assign a const char* to an char* const. When declaring

char name[MAX_NAME + 1];

You are declaring a constant memory address containing mutable char data (char* const). When you are passing a const char* to your function, you are passing a mutable pointer containing constant data. This will not compile. You should be doing a deep copy of the char array by using:

strcpy_s(dst, buffer_size, src);

This copy function will make sure that your array does not overflow, and that it is null terminated.

In order to be able to assign a pointer to a char array, it would need to be allocated on the heap with

char* name = new char[MAX_NAME + 1];

This would allow assigning a char* or char* const to it afterwards. You however need to manage the memory dynamically at this point, and I would advise against this in your case, as passing "Birth Tran" would lead to undefined behaviours as soon as char* const namee goes out of scope.

Upvotes: 0

eerorika
eerorika

Reputation: 238351

namee[0] == NULL
name[0] = NULL;

These are bugs. NULL is for pointers. name[0] as well as namee[0] is a char. It may work (by work, I mean it will assign the first character to be the null terminator character) on some systems because 0 is both a null pointer constant and an integer literal and thus convertible to char, and NULL may be defined as 0. But NULL may also be defined as nullptr in which case the program will be ill-formed.

Use name[0] = '\0' instead.

name[0] = *namee;

however it only applies the first letter of the string.

Well, you assign only the first character, so this is to be expected.

If you would like to copy the entire string, you need to assign all of the characters. That can be implemented with a loop. There are standard functions for copying a string though; You can use std::strncpy.

That said, constant length arrays are usually problematic because it is rarely possible to correctly predict the maximum required size. std::string is a more robust alternative.

Upvotes: 1

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