PHP Exercises: Check if a given non-negative given number is a multiple of 3 or 7, but not both

Last update on April 16 2025 12:52:29 (UTC/GMT +8 hours)

42. Multiple of 3 or 7 but Not Both

Write a PHP program to check if a given non-negative given number is a multiple of 3 or 7, but not both.

Sample Solution:

PHP Code :

<?php
// Define a function that checks if a number satisfies an exclusive OR (^) condition involving modulo operations
function test($n)
{
    // Check if the remainder of $n divided by 3 is 0 XOR the remainder of $n divided by 7 is 0
    return ($n % 3 == 0) ^ ($n % 7 == 0);
}

// Test the function with different values
var_dump(test(3));
var_dump(test(7));
var_dump(test(21));
?>

Explanation:

• Function Definition:
• The test function checks if a given number $n satisfies a specific condition using the exclusive OR (XOR) operator ^ with modulo operations.
• Condition Checked:
• The function evaluates whether:
• $n is divisible by 3 (i.e., $n % 3 == 0), XOR
• $n is divisible by 7 (i.e., $n % 7 == 0).
• The XOR operator returns true only if one of these conditions is true but not both.
• If either condition is met exclusively, the function returns true; otherwise, it returns false.

Output:

int(1)
int(1)
int(0)

Visual Presentation:

Flowchart:

For more Practice: Solve these Related Problems:

• Write a PHP script to verify if a non-negative number is a multiple of 3 or 7 exclusively, ensuring it is not divisible by both.
• Write a PHP function to test the divisibility of a number by 3 and 7 and return 1 if only one condition is met, or 0 otherwise.
• Write a PHP program to check for exclusive multiplicity by computing remainders for both 3 and 7 and applying XOR logic.
• Write a PHP script to use custom logic without built-in functions to determine if a number is divisible by 3 or 7 but not simultaneously.

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