将'char'赋值给'char [100]'的不兼容类型

Question

I am doing a review for school and I'm having a problem writing a function that creates a new struct and return a pointer to it.

// Review program

#include <iostream>
#include <stdlib.h>
#include <string>
#include <stdio.h>

using namespace std;
Book * makeBook(char * title, char * authorFName, char * authorLName, int numOfPages);

struct PersonName {
    char first[50];
    char last[50];
};
struct Book {
    char title[100];
    PersonName author;
    int numOfPages;
};

int main()
{
    char test[100] = "Hello, world";
    cout << test << endl;
    return 0;
}
Book * makeBook(char * title, char * authorFName, char * authorLName, int numOfPages)
{
    Book newBook;
    newBook.title = *title;

    Book* pBook = &newBook;
    return pBook;
}

The error, in the title, occurs because of newBook.title = *title; . Any help wpuld be appreciated.

Answer 1

It's correct, you cannot copy an array using the assignment operator.

Try strcpy(newBook.title, title) , or a variant with a maximum length.

strcpy is found in <string.h> or <cstring> .

Answer 2

*title is of type char. You are trying to assign that to an array of char. Hence the error.

You cannot assign arrays with the assignment operator. You need to perform a copy. For instance:

strcpy(newbook.title, title);

It's rather hard to know why you are eschewing the C++ standard string container and using C constructs for your strings.

There are more problems with your code. Not the least of which is where you return the address of a local variable out of the function. De-referencing that pointer invokes undefined behaviour and no good can come of that. A dynamic allocation is needed as things stand.

Your parameters should be const char* rather than char*. Using the latter makes it inconvenient to pass constand strings to your function.