mkdir variable type C++

Question

This is a part of the program I'm trying to create in C++.
Ever since starting with C++ I've had a problem with different variable types. The function mkdir requires const char I believe and I'm not sure how to convert the right variable from input to what I need.

All the variables and includes required are in the program. This is my only problem.

I might not be the most specific on my problem but I'm new to C++ and any help will be appreciated, thanks!

int createaccount(const char acc_name)
{
     int status = mkdir("/home/person/Desktop/Accounts/" + acc_name, S_IRWXU);
     return 0;
}

std::string new_acc_name;
cin >> new_acc_name;
new_acc_namechar = str.new_acc_namechar_str();
createaccount(new_acc_namechar);`

Answer 1

If you're working in C++, learn to use std::string . It is a built-in string type which can be converted to a const char* by calling c_str() . Normally you would store and pass around the std::string objects all the time unless you need to interface with something that takes a const char* . Call c_str() at that point. For example:

int createaccount(const std::string& acc_name)
{
     std::string path = "/home/person/Desktop/Accounts/" + acc_name;
     int status = mkdir(path.c_str(), S_IRWXU);
     return 0;
}

And after making a guess about what your code is trying to do:

std::string new_acc_name;
cin >> new_acc_name;
createaccount(new_acc_namechar);

Answer 2

int createaccount(const char acc_name)
{
     int status = mkdir("/home/person/Desktop/Accounts/" + acc_name, S_IRWXU);
     return 0;
}

in this function, you cannot just concatenate a const char* and a char using + operator. Instead you should use the int status = mkdir (string(string("/home/person/Desktop/Accounts/")+acc_name).c_str(), S_IRWXU);

Answer 3

mkdir() is a libc function that is declared as (according to man 2 mkdir ):

int mkdir(const char *pathname, mode_t mode);

so indeed, it takes a const char* as pathname. In C++, you are often dealing with std::string rather than the low level char* of C. you can use both to as "strings", but they are not interchangeable. std::string supports nice thingies like concatenating strings with the + operator and many more.

in your example, you are using + to concatenate "strings", but your strings are really char arrays, so you cannot simply concat them like that.

a simple solution would be:

int createaccount(const std::string&filename) {
   std::string path="/home/person/Desktop/Accounts/";
   std::string fullname=path+filename;
   int status = mkdir(fullname.c_str(), S_IRWXU); 
   return 0;
} 

which uses std::string for concatenating and the c_str() member function of std::string to convert the C++-string to C's const char*

Answer 4

I think what you want is something along the lines of:

int createaccount(const char acc_name) {
    std::string combinedPath = "/home/person/Desktop/Accounts" + acc_name;
    int status = mkdir(combinedPath.c_str(), S_IRWXU);
    return status;
}

Answer 5

"/home/person/Desktop/Accounts/" + acc_name this is adding acc_name, which is a single character, to the address of the string literal "/home/person/Desktop/Accounts/" . You want to do something like this.

int createaccount(const char acc_name)
{
  std::string dir = "/home/person/Desktop/Accounts/";
  dir += acc_name;
  int status = mkdir(dir.c_str(), S_IRWXU);
  return 0;
}