how would i go about determining the big o, theta, and omega of a piece of code?

i know assigning i = 0, j = 0, y = 0 is the constant 3 and becomes insignificant to big o. is while( i < 6 ) 6x? do i multiply everything in the loop by 6x?

Code:`void asdf() {`

int i = 0, j = 0, y = 0;

while( i < 6 ) {

j = 0;

while( j < 5 ) {

y = x = j;

y = x ^ y + i;

printf("x = %d y = %d\n", x,y);

j += 2;

} ++i;

}

}