Predefined String Functions in C: Explained

Mastering Predefined String Functions in C Programming

There are many pre-defined string-based functions in C, which are used to manipulate strings in various ways. These functions are declared in the string.h header file.

 Most commonly used pre-defined string-based functions in C:

• strlen(): Returns the length of a string.
• strcpy(): Copies a string to another string.
• strcat(): Concatenates two strings.
• strcmp(): Compares two strings and returns an integer value indicating whether they are equal, less than, or greater than each other.
• strstr(): Finds the first occurrence of a substring within a string.
• strtok(): Splits a string into tokens based on a delimiter character.
• strrev(): Reverses the order of characters in a string.
• strspn(): Returns the length of the initial substring of a string that consists only of characters from a specified set of characters.
• strcspn(): Returns the length of the initial substring of a string that does not contain any characters from a specified set of characters.
• strchr(): Finds the first occurrence of a character within a string.
• strrchr(): Finds the last occurrence of a character within a string.

These functions can be used to perform a variety of tasks, such as:

• Validating user input
• Parsing text files
• Generating dynamic strings
• Formatting output

How to use the strchr() function to find the first occurrence of the character 's' in a string:

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

int main() {
  char string[] = "This is a test string.";

  // Find the first occurrence of the character 's' in the string.
  char *ptr = strchr(string, 's');

  // If the character is found, print its position in the string.
  if (ptr != NULL) {
    printf("The first occurrence of the character 's' is at position %d.\n", ptr - string);
  } else {
    printf("The character 's' was not found in the string.\n");
  }

  return 0;
}

Output:

The first occurrence of the character 's' is at position 4.

Pre-defined string-based functions are a powerful tool for manipulating strings in C. By learning how to use these functions, you can write more efficient and concise code.

Further Reading:

Implementation of strncat() in C

add source string at the end of destination string

comparing two string using strcmp and strncmp

Design a function to copy to copy string into destination string using strcpy and strncpy

how to implement implementation of strncpy in c

Design a function to calculate the length of the string using strlen

pre defined string based function

Design a function using my_strcpy and using my_strchr we need to select given char in given string

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