How do I convert ifstream or string input to char?

Question

In this method,

void mainRoutine(char *pattern, string searchPattern)
{
        cout << "Please enter the string pattern to be searched: " << endl;
        getline(cin, searchPattern);
        ifstream filename(searchPattern.c_str());
        while(filename.good() && filename.peek() != EOF)
        {
                cout << (char)filename.get();
        }
        cout << "\n";
        char *pattern = (char *)filename;
}

When the user inputs a string - the filename to be taken in, I want to convert this string into a char so I can use it in other methods. How can I do this?

Instead of "convert this string into a char", do you perhaps mean convert it into a char pointer? — Vaughn Cato
– Vaughn Cato, Commented Apr 4, 2014 at 4:43
Making a char* from std::string is simple - call c_str() method on the string. — Sergey Kalinichenko
– Sergey Kalinichenko, Commented Apr 4, 2014 at 4:47
Your code shouldn't even compile on a respectable compiler. The last line: char *pattern = (char *)filename; is not valid. You could however grab a local, read-only char pointer to a string with: const char * pName = filename.c_str(); Bare in mind that the pointer is only valid inside the scope of the current function. — glampert
– glampert, Commented Apr 4, 2014 at 4:57

user657267 · Accepted Answer · 2014-04-04 05:17:32Z

1

Just return the std::string

std::string mainRoutine()
{
  std::string searchPattern;
  std::cout << "Please enter the string pattern to be searched: \n";
  std::cin >> searchPattern;

  std::cout << std::ifstream(searchPattern).rdbuf() << '\n';
  // searchPattern.c_str() if not using c++11

  return searchPattern
}

answered Apr 4, 2014 at 5:17

user657267

21.1k5 gold badges65 silver badges81 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

darkboss019 · Accepted Answer · 2014-04-04 05:00:46Z

0

char* chFilNam = new char[fileName.length() + 1];
memcpy(chFilNam,fileName.c_str(),fileName.length());

edited Apr 4, 2014 at 5:00

answered Apr 4, 2014 at 4:55

darkboss019

112 bronze badges

1 Comment

glampert Over a year ago

You should use strcpy() instead. memcpy() won't copy the null terminator, thus leaving chFilNam in an invalid state to be used as a C string.

Collectives™ on Stack Overflow

How do I convert ifstream or string input to char?

2 Answers 2

Comments

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related