PHP strncmp() Function

The strncmp() is an inbuilt function in PHP which is used to compare first n character of two strings. This function is case-sensitive which points that capital and small cases will be treated differently, during comparison. This function compares two strings with first n character and tells whether the first string is greater or smaller or equal to the second string.

int strncmp( $str1, $str2, $len )

Parameters: This function accepts three parameters as mentioned above and described below: 

• $str1: It is mandatory parameter. This parameter refers to the first string to be used in the comparison.
• $str2: It is mandatory parameter. This parameter refers to the second string to be used in the comparison.
• $len: It is mandatory parameter which is used to define the first $len number of characters compared.

Return Value: This function returns a random integer value depending on the comparison of string which is given below: 

• Returns 0 if the first n character of both strings are equal.
• Returns a negative value ( < 0), if the first n character of $string2 is greater than $string1.
• Returns a positive value ( > 0), if the first n character of $string1 is greater than $string2.

Below programs illustrate the strncmp() function in PHP.

Program 1:

PHP

<?php

// PHP program to illustrate the working of strncmp()
$str1 = "Welcome to GFG";
$str2 = "Welcome to GeeksforGeeks";
$str3 = "Welcome";

// In this case both the strings are equal
print_r(strncmp($str1, $str3, 7));
echo "\n";

// In this case the first is greater
print_r(strncmp($str2, $str1, 14));
echo "\n";

// In this case the second is greater
print_r(strncmp($str3, $str2, 10))

?>

Output:

0
31
-3

Program 2:

PHP

<?php

// PHP program to illustrate the working of strncmp()
$str1 = "GeeksforGeeks";
$str2 = "geeksforgeeks";

// In this case both the strings are equal
print_r(strncmp($str1, $str2, 13));

?>

Output:

-32

Reference: http://php.net/manual/en/function.strncmp.php