C String Handling

📚 C String Handling – Mastering String Operations in C

In C, strings are arrays of characters, and string handling involves manipulating those arrays in various ways. This tutorial covers key string operations, including copying, concatenation, searching, and modifying strings, along with important considerations regarding memory management.

🔹 String Declaration and Initialization

In C, a string is declared as a character array. The string is initialized with a set of characters followed by a null character \0 to mark the end of the string.

📝 Example 1: Declaring and Initializing a String

Here, we declare a string and initialize it:

#include <stdio.h>

int main() {
    char str[] = "Hello, World!"; // Declaring and initializing a string
    printf("String: %s\n", str);
    
    return 0;
}
  

🔹 String Memory Allocation

In C, strings can also be dynamically allocated using malloc(). This allows you to allocate memory for a string at runtime.

📝 Example 2: Dynamically Allocating Memory for a String

Here, we allocate memory for a string using malloc():

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

int main() {
    char *str;
    str = (char *)malloc(20 * sizeof(char)); // Allocate memory for a string
    
    strcpy(str, "Dynamically Allocated!"); // Copying string to allocated memory
    printf("String: %s\n", str);
    
    free(str); // Free allocated memory
    return 0;
}
  

🔹 strcpy – Copying Strings

The strcpy() function copies the content of one string to another. The destination string must have enough memory to hold the copied content.

📝 Example 3: Using strcpy to Copy a String

In this example, we copy the string using strcpy:

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

int main() {
    char src[] = "Hello, World!";
    char dest[20]; // Ensure sufficient space for the copied string
    
    strcpy(dest, src); // Copy string from src to dest
    printf("Destination String: %s\n", dest);
    
    return 0;
}
  

🔹 strcat – Concatenating Strings

The strcat() function concatenates (joins) two strings. It appends the second string to the end of the first string.

📝 Example 4: Using strcat to Concatenate Strings

In this example, we concatenate two strings:

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

int main() {
    char str1[30] = "Hello";
    char str2[] = " World!";
    
    strcat(str1, str2); // Concatenate str2 to str1
    printf("Concatenated String: %s\n", str1);
    
    return 0;
}
  

🔹 strlen – Finding String Length

The strlen() function returns the length of a string, excluding the null character \0.

📝 Example 5: Using strlen to Find String Length

This example shows how to use strlen to find the length of a string:

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

int main() {
    char str[] = "C Programming!";
    
    int length = strlen(str); // Get length of the string
    printf("Length of String: %d\n", length);
    
    return 0;
}
  

🔹 strcmp – Comparing Strings

The strcmp() function compares two strings lexicographically. It returns:

• 0 if the strings are equal,
• a negative value if the first string is lexicographically less than the second,
• a positive value if the first string is lexicographically greater than the second.

📝 Example 6: Using strcmp to Compare Strings

Here, we compare two strings using strcmp:

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

int main() {
    char str1[] = "C Programming";
    char str2[] = "C Programming";
    
    int result = strcmp(str1, str2); // Compare str1 and str2
    
    if (result == 0) {
        printf("Strings are identical\n");
    } else {
        printf("Strings are different\n");
    }
    
    return 0;
}
  

🎯 Key Points on C String Handling

• Strings are arrays of characters in C and require proper memory management.
• strcpy() copies one string to another, strcat() concatenates strings, and strlen() returns the length of a string.
• Memory for strings can be dynamically allocated using malloc() and should be freed using free() when no longer needed.

💡 Practice Challenge

Try modifying the examples and experiment with other string operations, such as reversing a string, searching for a substring, or converting string cases. Keep practicing to master string handling in C!