Answer:
The strcmp function is a commonly used string comparison function in the C programming language. It is defined in the string.h header file and is used to compare two strings lexicographically. The function takes two string arguments and returns an integer value that indicates the relationship between the two strings.
The strcmp function compares the characters of the two strings starting from the first character and continues until it finds a difference or reaches the end of either string. It compares the ASCII values of the corresponding characters in both strings. If the ASCII values are equal, it moves on to compare the next characters. The function stops comparing as soon as it finds a difference in the characters or reaches the end of either string.
The return value of strcmp is based on the result of the comparison. If the two strings are equal, strcmp returns 0. If the first string is greater than the second string (in lexicographical order), it returns a positive integer value. Conversely, if the first string is less than the second string, it returns a negative integer value.
It is important to note that strcmp is case-sensitive, meaning that uppercase and lowercase letters are considered different characters. For example, "apple" and "Apple" would be considered different strings by strcmp.
In addition to strcmp, there are other related functions for string comparison in C, such as strncmp and strcasecmp. The strncmp function allows you to specify a maximum number of characters to compare, while strcasecmp performs a case-insensitive comparison.
Overall, strcmp is a fundamental function for comparing strings in C and plays a crucial role in various applications where string comparison is required.