PHP Recursive Function

Tutorial by: Adam Lim


For example we need to create calculation as below:
5 => (5*2)+(4*2)+(3*2)+(2*1)+(1*1)

It can be resolved by for loop as below:

$total=0;
for($i=5; $i=0; $i--){
  $total += $i * 2;
}


To create a recursive function, it should as follow:

function test($int){
  if($int>0){
    echo $int.<br>;
    return(($int*2) + test($int-1));     // call back self function to continue loop
  }else{
    return 0;
  }
}

echo test(5);

Output:
5
4
3
2
1
30

DEMO