C gets() and puts() functions

The gets() and puts() functions are input/output functions in the C programming language. However, I must inform you that the gets() function is considered unsafe and has been deprecated since the C11 standard due to its potential to cause buffer overflow vulnerabilities. It is highly recommended to avoid using gets() and use safer alternatives instead.

Here’s a brief explanation of both functions:

  1. gets(): The gets() function was traditionally used to read a line of text from the standard input (keyboard) and store it as a string in a character array. However, it has no way of knowing the size of the destination array, which makes it prone to buffer overflow errors. This is because gets() reads characters from input until it encounters a newline character (‘\n’) or the end of the input file, and it stores these characters into the provided buffer without any bounds checking. Consequently, if the input exceeds the size of the buffer, it can overwrite adjacent memory locations, leading to unpredictable behavior and security vulnerabilities.

Example usage of gets():

char buffer[50];
printf("Enter a string: ");
gets(buffer); // Unsafe: potential buffer overflow
  1. puts(): The puts() function is used to write a null-terminated string to the standard output (usually the console). It takes a character array (string) as an argument and displays it on the output screen followed by a newline character. Unlike gets(), puts() does not suffer from buffer overflow vulnerabilities since it does not accept any user input.

Example usage of puts():

char str[] = "Hello, World!";
puts(str); // Outputs "Hello, World!"

In modern C programming, it is recommended to use safer alternatives to gets(), such as fgets() or scanf(), which allow you to specify the maximum number of characters to read and provide more control over input limits. Similarly, printf() is often used instead of puts() for writing formatted output.