Tutorials

C strdup() Function

Posted in C Tutorial

Updated on Nov 16, 2024

By Mari Selvan

👁️ 392 - Views

⏳ 4 mins

💬 1 Comment

Photo Credit to CodeToFun

🙋 Introduction

In C programming, working with strings is a common and essential task.

The strdup() function is a useful standard library function that duplicates a given string.

It allocates memory for the new string and copies the content of the original string into the newly allocated memory.

In this tutorial, we'll explore the usage and functionality of the strdup() function in C.

💡 Syntax

The syntax for the strdup() function is as follows:

Syntax

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char *strdup(const char *source);

source: The string to be duplicated.

📄 Example

Let's dive into an example to illustrate how the strdup() function works.

strdup.c

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#include <stdio.h>
#include <string.h>
#include <stdlib.h>

int main() {
  const char * originalString = "Hello, C!";

  // Duplicate the string
  char * copiedString = strdup(originalString);

  // Check if the duplication was successful
  if (copiedString != NULL) {
    printf("Original: %s\n", originalString);
    printf("Copied: %s\n", copiedString);

    // Free the memory allocated by strdup
    free(copiedString);
  } else {
    fprintf(stderr, "Memory allocation failed.\n");
  }

  return 0;
}

💻 Output

Output

Original: Hello, C!
Copied: Hello, C!

🧠 How the Program Works

In this example, the strdup() function is used to duplicate the string "Hello, C!" into a new dynamically allocated memory. The original and copied strings are then printed, and the dynamically allocated memory is freed using the free() function.

↩️ Return Value

The strdup() function returns a pointer to the duplicated string if the allocation is successful. If there is insufficient memory, it returns NULL.

📚 Common Use Cases

The strdup() function is particularly useful when you need to create a duplicate of a string and modify the duplicated string without affecting the original. It simplifies memory management by handling the allocation for you.

📝 Notes

Remember to free the memory allocated by strdup() using the free() function to prevent memory leaks.
If you're working in an environment where strdup() is not available, you can implement a similar function using malloc() and strcpy().

🎢 Optimization

The strdup() function is optimized for convenience, but keep in mind that it involves dynamic memory allocation, which can lead to memory fragmentation if not managed properly. Be mindful of freeing the allocated memory when it is no longer needed.

🎉 Conclusion

The strdup() function in C is a valuable tool for duplicating strings and simplifying memory management in string operations. It provides a convenient way to create independent copies of strings for manipulation.

Feel free to experiment with different strings and explore the behavior of the strdup() function in various scenarios. Happy coding!