/*
(Exercise 3-3)
Write a function expand(s1, s2) that expands shorthand notations like a - z in
the string s1 into the equivalent complete list abc...xyz in s2. Allow for letters of either case
and digits, and be prepared to handle cases like a - b - c and a - z0 - 9 and - a - z.Arrange that a
leading or trailing - is taken literally.
*/
void expand(char s1[], char s2[]) {
// Parse through s1
int currentChar;
for (int i = currentChar = 0; s1[i] != '\0' && s1[i+1] != '\0' && s1[i+2] != '\0'; ++i) {
// Detect if the sequence 'lowercase char' '-' 'lowercase char' is found OR
// Detect if the sequence 'uppercase char' '-' 'uppercase char' is found OR
// Detect if the sequence 'digit' '-' 'digit' is found
if ((isLowercaseAlpha(s1[i]) && s1[i + 1] == '-' && isLowercaseAlpha(s1[i + 2]))
|| (isUppercaseAlpha(s1[i]) && s1[i + 1] == '-' && isUppercaseAlpha(s1[i + 2]))
|| (isdigit(s1[i]) && s1[i + 1] == '-' && isdigit(s1[i + 2]))) {
// Then replace the currentChar in s2 with the appropriate sequence
// The question assumes that the first char comes before the second
// However, the alternative is possible as well as the case where it is a-a
int trich;
if (s1[i] <= s1[i + 2]) // If it looks like a-z
trich = 1;
else // If it looks like z-a
trich = -1;
char c = s1[i];
while (c != s1[i + 2]) {
s2[currentChar] = c;
c += trich;
++currentChar;
}
s2[currentChar] = c;
++currentChar;
// Increment i by 2
i += 2;
}
else {
s2[currentChar] = s1[i];
++currentChar;
}
}
s2[currentChar] = '\0';
}
/* isBothLower: receives two integers and determines if they both represent
lowercase chars in the characterset*/
int isBothLower(int a, int b)
{
return isLowercaseAlpha(a) && isLowercaseAlpha(b);
}
/* isAlphabetic: determines whether or not a char is an alpha char in
either lowercase or uppercase range. */
int isAlphabetic(int c)
{
return isLowercaseAlpha(c) || isUppercaseAlpha(c);
}