Refactoring simple card counting function into multiple functions? - c

Question

I'm just starting to learn C from Head First C, but I'm having difficulty understanding how refactor my code into multiple functions, more specifically, I don't know how to get functions to work and am confused how to take user input.
How would I incorporate a function like the one below into the main function? What are some other function examples I could use to refactor? Thank you so much!
void get_card_name(char *prompt, char *card_name)
Main function
int main()
{
char card_name[3];
int count = 0;
while ( card_name[0] != 'X' ) {
puts("Enter the card_name: ");
scanf("%2s", card_name);
int val = 0;
switch(card_name[0]) {
case 'K':
case 'Q':
case 'J':
val = 10;
break;
case 'A':
val = 11;
break;
case 'X':
continue;
default:
val = atoi(card_name);
if ((val < 1) || (val > 10)) {
puts("I dont understand that value!");
continue;
}
}
if ((val > 2) && (val < 7)) {
count++;
} else if (val == 10) {
count--;
}
printf("Current count: %i\n", count);
}
return 0;
}

Answer 1

The generic answer when it comes to refactoring is "If it looks complicated or hard to read, try to break it down into smaller pieces that are easier to read (and understand).".
In your case you have this:
int main() {
/* Initial state needed later on */
/* Do some complicated stuff */
}
To refactor this, you need to find out what parts of the initial state you need to keep close to whatever you are going to move away into its own function. In your example, card_name and count are both used inside the complicated bit, and nowhere else. So you can, and should, keep those close the complicated bits:
void do_card_stuff() {
char card_name[3];
int count = 0;
/* Do some complicated stuff */
}
int main() {
do_card_stuff();
}
And, lo and behold, you've refactored your code. If you still think that the card stuff looks complicated, try to break it up into more pieces:
int get_card_value(char card) {
/* Do some complicated stuff */
return value;
}
int do_card_stuff() {
char card_name[3];
int count = 0;
int value;
/* Loop */
/* Get card value from user */
value = get_card_value(card_name[0]);
}
int main() {
do_card_stuff();
}
Just keep at it until it's just silly to break it into smaller bits and you're done. Also, try to keep in mind that the code you break out should be as generic as possible since this will let you re-use this code later on (potentially in other projects).