Common String Functions

C programming provides a set of standard library functions for manipulating strings. These functions are declared in the <string.h> header file and offer various operations to work with character arrays. Let's explore some common string functions and their usage.

1. strlen - String Length

#include <string.h>

size_t strlen(const char *str);

This function returns the length of the input string, excluding the null character. It calculates the number of characters in the string.

const char *message = "Hello, World!";
size_t length = strlen(message); // Returns 13

2. strcpy - String Copy

#include <string.h>

char *strcpy(char *dest, const char *src);

This function copies the contents of the source string (src) to the destination string (dest). It includes the null character in the copied sequence.

char source[] = "Copy me!";
char destination[20];
strcpy(destination, source); // destination now contains "Copy me!"

3. strcat - String Concatenate

#include <string.h>

char *strcat(char *dest, const char *src);

This function appends the contents of the source string (src) to the destination string (dest). The destination string must have enough space to accommodate both strings.

char greeting[20] = "Hello";
strcat(greeting, ", World!"); // greeting now contains "Hello, World!"

4. strcmp - String Compare

#include <string.h>

int strcmp(const char *str1, const char *str2);

This function compares two strings (str1 and str2) lexicographically. It returns an integer less than, equal to, or greater than zero, indicating whether the first string is less than, equal to, or greater than the second string.

const char *string1 = "apple";
const char *string2 = "banana";
int result = strcmp(string1, string2); // Returns a value < 0

5. strncpy - String Copy with Length Limit

#include <string.h>

char *strncpy(char *dest, const char *src, size_t n);

This function copies at most n characters from the source string (src) to the destination string (dest). It ensures that the destination is null-terminated if n is sufficient.

char source[] = "Copy me!";
char destination[5];
strncpy(destination, source, 4); // destination now contains "Copy"

These are just a few examples of the many string functions available in C. Understanding and using these functions appropriately will enhance your ability to work with strings in C programming.

If you have specific questions or if there are additional topics you'd like to explore, feel free to ask!