Check if integer is multiple of 8

Use the "modulo" operator, which gives the remainder from division:

if (n % 8 == 0) {
    // n is a multiple of 8
}

Use the "modulo" or "integer remainder operator" %:

int a = ....;
if (a % 8 == 0 ) {
  // a is amultiple of 8
}

use operator %

if ( num % 8 == 0 )
{
    // num is multple of 8
}