A Guide to C String Manipulation Functions

C is a versatile and powerful programming language known for its low-level memory manipulation capabilities. One of the fundamental data types in C is the string, which is essentially an array of characters terminated by a null character ('\0'). To work with strings effectively, C provides a set of standard library functions for string manipulation. In this article, we will explore these essential C string manipulation functions.

1. strlen() – String Length

The strlen() function is used to determine the length of a null-terminated string. It counts the number of characters in the string until it encounters the null character and returns the length as an integer.

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

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

2. strcpy() – String Copy

The strcpy() function is used to copy one string into another. It takes two arguments: the destination string and the source string. The function copies the characters from the source string to the destination string until it reaches the null character in the source string.

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

int main() {
    char source[] = "Hello, World!";
    char destination[20];

    strcpy(destination, source);

    printf("Copied string: %s\n", destination);
    return 0;
}

3. strcat() – String Concatenation

The strcat() function is used to concatenate (append) one string to the end of another. It takes two arguments: the destination string and the source string. The function appends the characters from the source string to the end of the destination string.

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

int main() {
    char str1[20] = "Hello, ";
    char str2[] = "World!";

    strcat(str1, str2);

    printf("Concatenated string: %s\n", str1);
    return 0;
}

4. strcmp() – String Comparison

The strcmp() function is used to compare two strings lexicographically. It returns an integer value that indicates whether the strings are equal, greater than, or less than each other. A return value of 0 indicates that the strings are equal.

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

int main() {
    char str1[] = "apple";
    char str2[] = "banana";

    int result = strcmp(str1, str2);

    if (result < 0) {
        printf("str1 is less than str2\n");
    } else if (result > 0) {
        printf("str1 is greater than str2\n");
    } else {
        printf("str1 is equal to str2\n");
    }

    return 0;
}

5. strtok() – String Tokenization

The strtok() function is used to split a string into tokens based on a specified delimiter. It can be used to parse a sentence or a line of text into individual words or parts.

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

int main() {
    char str[] = "apple,banana,cherry";
    char *token = strtok(str, ",");

    while (token != NULL) {
        printf("%s\n", token);
        token = strtok(NULL, ",");
    }

    return 0;
}

Conclusion

C string manipulation functions are essential for working with strings in C programming. These functions provide the building blocks for many common string operations, such as copying, concatenating, comparing, and tokenizing strings. Understanding and using these functions effectively is crucial for C programmers to manipulate and process textual data in their programs.