How to Read Lines Containing Spaces from a Text File in C

When working with text files in C, it's essential to understand how to properly read and process the content, especially when the file contains spaces. This article explores techniques and examples on how to read lines with spaces from a text file using C programming.

Reading Files in Binary Mode vs. Text Mode

In C, reading a file can be achieved in two primary modes: binary and text. The default mode is text, which means that certain characters such as the newline character ( ) are automatically translated based on the system's locale settings. However, if you need to read the exact content of a file as it is stored, including raw binary data, it's better to use binary mode.

If you need to read the file as binary, you can do so by opening the file in binary mode. Here's an example of how to use binary mode with C streams:

#include fstream
size_t get_file_size(std::ifstream file) {
    (0, std::ios::end);
    size_t filesize  ();
    (0, std::ios::beg);
    return filesize;
}
int main() {
    std::ifstream file;
    (example.txt, std::ios::binary);
    if (!_open()) {
        std::cerr  Failed to open file.  std::endl;
        return 1;
    }
    const size_t filesize  get_file_size(file);
    char *buffer  new char[filesize];
    (buffer, filesize);
    ();
    // Now buffer contains the exact content of the file
    free(buffer);
    return 0;
}

Reading Entire Lines Containing Spaces

When your file contains lines with spaces, using the getline function is a much better approach than using the formatted stream extraction operator () or character-by-character processing. getline reads the entire line, including spaces, and stores it in a std::string.

Here is an example C program that demonstrates the use of getline to read lines with spaces:

#include iostream
#include string
using namespace std;
int main() {
    string name;
    cout  Enter your name: ;
    getline(cin, name);
    cout  Hello   name   welcome to gfg  endl;
    return 0;
}

Output Example

When you run the program, the output would look like this:

Enter your name: mykaty

Hello mykaty welcome to gfg

Conclusion

Reading lines containing spaces from a text file in C requires the right techniques to ensure the content is accurately processed. Whether you choose to read files in binary mode or use getline to read entire lines, the approach you choose can significantly affect the outcome of your program. Understanding these methods will help you handle text files more effectively in C programming.

Keywords

C programming, file I/O, getline function