How do you compute the time complexity for the following function?

Show steps and explanation when possible please, thanks.

void tower_Of_Hanoi(int num, char peg, char peg_to, char peg_aux)

{

//Compute the difference value.

int difference = peg - peg_to;

//Check the validity from the if condition.

if (difference == 1 || difference == -1)

{

//Check the value of num

if (num == 1)

{

//Display the output message.

printf(" The disk 1 moved from %c to %c ", peg, peg_to);

//Ret

return;

}

//Call the function recursively.

tower_Of_Hanoi(num - 1, peg, peg_aux, peg_to);

//Display the output message.

printf(" The disk %d moved from %c to %c ", num, peg, peg_to);

//function call

tower_Of_Hanoi(num - 1, peg_aux, peg_to, peg);

}

//"else" part

else

{

//Call the function recursively.

tower_Of_Hanoi(num, peg, peg_aux, peg_to);

//Call the function recursively.

tower_Of_Hanoi(num, peg_aux, peg_to, peg);

}

}