Question

Using PHP:

1. Write a function that:

• Given a numerical parameter in input, computes and prints all the prime numbers up to that value.

Example:

If input parameter is 10, output is "2, 3, 5, 7"

If input parameter is 100, output is "2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97"

2. Write a "tester function" that:

• Given a specific subset of inputs, tests the function described above (point 1).

Example, in pseudo code:

tester_function:   
   is output from prime_function(10) equal to "2, 3, 5, 7"? If yes, test passed
   is output from prime_function(0) equal to ""? If yes, test passed
   ...

Answer 1

Here is the PHP code to print all the prime number up to the given value:

<?php
//prints list of prime numbers till given number
function print_function($num){
for ($i = 1; $i <= $num ; $i++){
if(isPrime($i) == 1){
echo $i;
echo ", ";
}
}
  
}
//to check the given number prime or not
function isPrime($num){
   if ($num == 1)
   return 0;
   for ($i = 2; $i <= $num/2; $i++){
       if ($num % $i == 0)
           return 0;
   }
   return 1;
}

print_function(100);

?>

Screenshot of the code:

Output of the above program :

for , print_function(100):

for print_function(0): Nothing printed