1. You can run into a buffer overflow when the user types in more than 15 characters. You should use scanf("%15s", &plate); - Note that scanf will automatically add the null terminator (hence 15 instead of 16).

2. While it is accepted to use single letter variable for loop you have abused this extensively in your sorting routine.

• What is a, what is length, what is string_size? Just from reading the method (without reading main) it's very hard to figure out what the individual parameters are supposed to mean.

• Why is length const but string_size isn't?

• Why are you copying parameters and ALPHABET1 into local variables which have short meaningless names?

1. You can run into a buffer overflow when the user types in more than 15 characters. You should use scanf("%15s", &plate); - Note that scanf will automatically add the null terminator (hence 15 instead of 16).

2. While it is accepted to use single letter variables for loops you have abused this extensively in your sorting routine.

• What is a, what is length, what is string_size? Just from reading the method (without reading main) it's very hard to figure out what the individual parameters are supposed to mean.

• Why is length const but string_size isn't?

• Why are you copying the parameters and ALPHABET into local variables which have short meaningless names?

All in all the code is fairly clean, but you should de-obfuscate it a bit.