skipping a character in an array if previous character is the same - c++

Question

I'm iterating through an array of chars to do some manipulation. I want to "skip" an iteration if there are two adjacent characters that are the same.
e.g. x112abbca
skip----------^
I have some code but it's not elegant and was wondering if anyone can think of a better way? I have a few case's in the switch statement and would be happy if I didn't have to use an if statement inside the switch.
switch(ent->d_name[i])
{
if(i > 0 && ent->d_name[i] == ent->d_name[i-1])
continue;
case ' ' :
...//code omited
case '-' :
...
}
By the way, an instructor once told me "avoid continues unless much code is required to replace them". Does anyone second that? (Actually he said the same about breaks)

Answer 1

Put the if outside the switch.
While I don't have anything against using continue and break, you can certainly bypass them this time without much code at all: simply revert the condition and put the whole switch statement within the if-block.
Answering the rectified question: what's clean depends on many factors. How long is this list of characters to consider: should you iterate over them yourself, or perhaps use a utility function from <algorithm>? In any case, if you are referring to the same character multiple times, perhaps you ought to give it an alias:
std::string interesting_chars("-_;,.abc");
// ...
for (i...) {
char cur = abc->def[i];
if (cur != prev || interesting_chars.find(cur) == std::string::npos)
switch (current) // ...

Answer 2

char chr = '\0';
char *cur = &ent->d_name[0];
while (*cur != '\0') {
if (chr != *cur) {
switch(...) {
}
}
chr = *cur++;
}

Answer 3

If you can clobber the content of the array you are analyzing, you can preprocess it with std::unique():
ent->erase(std::unique(ent->d_name.begin(), ent->d_name.end()), ent.end());
This should replace all sequences of identical characters by a single copy and shorten the string appropriately. If you can't clobber the string itself, you can create a copy with character sequences of just one string:
std::string tmp;
std::unique_copy(ent->d_name.begin(), ent->d_name.end(), std::back_inserter(tmp));
In case you are using C-strings: use std::string instead. If you insist in using C-strings and don't want to play with std::unique() a nicer approach than yours is to use a previous character, initialized to 0 (this can't be part of a C-string, after all):
char previous(0);
for (size_t i(0); ent->d_name[i]; ++i) {
if (ent->d_name[i] != previous) {
switch (previous = ent->d_name[i]) {
...
}
}
}

Answer 4

I hope I understand what you are trying to do, anyway this will find matching pairs and skip over a match.
char c_anotherValue[] = "Hello World!";
int i_len = strlen(c_anotherValue);
for(int i = 0; i < i_len-1;i++)
{
if(c_anotherValue[i] == c_anotherValue[i+1])
{
printf("%c%c",c_anotherValue[i],c_anotherValue[i+1]);
i++;//this will force the loop to skip
}
}