PHP Exercises: Check if the bits of the two given positions of a number are same or not

PHP: Exercise-34 with Solution

Write a PHP program to check if the bits of the two given positions of a number are same or not.

112 - > 01110000
Test 2nd and 3rd position
Result: True
Test 4th and 5th position
Result: False

Sample Solution:

PHP Code:

<?php
// Function to test if bits at two specified positions are equal
function test_bit_position($num, $pos1, $pos2) {
    // Adjust positions to start from 0 (as arrays in PHP are 0-indexed)
    $pos1--;
    $pos2--;
    
    // Convert the decimal number to a binary string and reverse it
    $bin_num = strrev(decbin($num));

    // Check if the bits at the specified positions are equal
    if ($bin_num[$pos1] == $bin_num[$pos2]) {
        return "true";
    } else {
        return "false";
    }
}

// Test case
echo test_bit_position(112, 5, 6) . "\n";

?>

Explanation:

• Function Definition:
• The test_bit_position($num, $pos1, $pos2) function checks if the bits at two specified positions in a number's binary representation are equal.
• Adjust Bit Positions:
• $pos1-- and $pos2-- adjust the positions to be zero-indexed, as PHP strings are zero-indexed (e.g., position 1 becomes 0).
• Convert Number to Binary:
• decbin($num) converts the decimal number $num to a binary string.
• strrev() reverses the binary string to match the bit positions from right to left, making it easier to access bits by index.
• Check Equality of Specified Bits:
• The function checks if the bits at the adjusted positions $pos1 and $pos2 are equal:
• If they are, it returns "true".
• If not, it returns "false".
• Test Case:
• The function is tested with the number 112 and positions 5 and 6.
• The result is printed with echo.

Output:

true

Flowchart:

PHP Code Editor:

Have another way to solve this solution? Contribute your code (and comments) through Disqus.

Previous: Write a PHP program to convert word to digit.
Next: Write a PHP program to remove duplicates from a sorted list.