How does the strcat() function work in C

Understanding strcat() in C

The strcat() function in C is used to concatenate (append) one string to another. It is declared in the <string.h> library.

Syntax

• destination: The string to which source will be appended.
• source: The string to be appended to destination.
• Returns: A pointer to the destination string.

Important Notes:

• The destination string must have enough space to accommodate the concatenated result.
• strcat() modifies destination in place.
• The source string remains unchanged.

Example 1: Basic Usage

Output:

Example 2: Concatenating Multiple Strings

Output:

Example 3: Buffer Overflow Risk

Potential Issue:

• If str1 does not have enough space, buffer overflow occurs, which can lead to crashes or unexpected behavior.

Safe Alternative: strncat()

To avoid buffer overflow, use strncat():

• Ensures that only n characters are appended.

Example:

Key Takeaways

✔ strcat() is used to append one string to another.
✔ The destination array must have enough space to hold the concatenated string.
✔ Use strncat() to prevent buffer overflow.

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