如何将用户输入的char *追加到const char *的初始化中

Question

I am trying to create a connection to a postgres database from C++ and ask for the password from the user. Here is the code in question:

    char* pass;
    cout << "Please enter password for user: Mickey" << endl;
    cin >> pass;

    const char *connectInfo = "host=cs-linux dbname=gbianchet user=mickey password=" + pass;

I am wondering how I can get the user's input and append it to the end of the the initialization for connectInfo.

I have searched for the answer to this question and have found these links, Initialize const char* by concatenating another char* and How to cleanly use: const char* and std::string? , but they don't quite answer my question.

Any help would be much appreciated.

Thanks

Answer 1

The references you gave in your question are actually not appending or concatenating in const char * they used Preprocessor Directives

This is the easy and proper way to achieve the same thing

string pass;
cout << "Please enter password for user: Mickey" << endl;
getline(cin, pass);
string connectionString("host=cs-linux dbname=gbianchet user=mickey password=" + pass);
const char *connectInfo = connectionString.c_str();

include string class header in your source code as #include <string> string class is in std namespace

Answer 2

http://www.cplusplus.com/reference/string/string/c_str/

Create your desired string using c++ string and then call the method .c_str() (see the above link)

For a given c++ string, it'll return you a NULL terminated c-string version of the c++ string that you can pass to your function that expects a c-string.