# PHP functions - Exercises, Practice, Solution

## PHP functions [ 6 exercises with solution]

1. Write a function to calculate the factorial of a number (a non-negative integer). The function accepts the number as an argument. Go to the editor

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2. Write a function to check whether a number is prime or not. Go to the editor
Note: A prime number (or a prime) is a natural number greater than 1 that has no positive divisors other than 1 and itself.

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3. Write a function to reverse a string. Go to the editor

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4. Write a function to sort an array. Go to the editor

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5. Write a PHP function that checks whether a string is all lowercase. Go to the editor
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6. Write a PHP function that checks whether a passed string is a palindrome or not? Go to the editor
A palindrome is a word, phrase, or sequence that reads the same backward as forward, e.g., madam or nurses run.

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PHP Code Editor:

More to Come !

Do not submit any solution of the above exercises at here, if you want to contribute go to the appropriate exercise page.

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## PHP: Tips of the Day

In PHP, there are two versions of logical AND and OR operators.

Operator True if
\$a and \$b Both \$a and \$b are true
\$a && \$b Both \$a and \$b are true
\$a or \$b Either \$a or \$b is true
\$a || \$b Either \$a or \$b is true

Note that the && and || opererators have higher precedence than and and or. See table below:

Evaluation Result of \$e Evaluated as
\$e = false || true True \$e = (false || true)
\$e = false or true False (\$e = false) or true

Because of this it's safer to use && and || instead of and and or.