How to import file contents into the program in c++

There are two common ways to read data from a file in C: open the file using a file stream, read the data in, and close the file. Use the C standard library functions fopen, fread, fwrite, and fclose for file processing.

How to read data from a file in C

In C, read data from a file There are two common methods:

1. Use file stream

File stream is a way of processing files in C. It provides a set of functions to read Write file. To read a file using a file stream, you need to perform the following steps:

• Open a file: Use the ifstream class to open a file.
• Read data: Use functions such as operator>> or getline to read data from the file.
• Close the file: Use the close function to close the file.

Sample code:

<code class="cpp">#include <fstream>
#include <iostream>

int main() {
  std::ifstream file("data.txt");
  if (file.is_open()) {
    std::string line;
    while (std::getline(file, line)) {
      std::cout << line << std::endl;
    }
    file.close();
  }
  return 0;
}</code>

2. Using C standard library functions

The C standard library also provides a set of functions to process files :

• fopen: Open the file.
• fread: Read data from the file.
• fwrite: Write data to the file.
• fclose: Close the file.

Sample code:

<code class="cpp">#include <stdio.h>

int main() {
  FILE *file = fopen("data.txt", "r");
  if (file != NULL) {
    char buffer[1024];
    while (fread(buffer, sizeof(char), 1024, file) != 0) {
      printf("%s", buffer);
    }
    fclose(file);
  }
  return 0;
}</code>

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