String manipulation , at a complete loss - c++

Question

I am trying to grab sub-strings out of a larger string and I have got it to work in a small program but when I try to run it into the real program it just goes wrong. I am building off someone else s function and got it to work for my purpose, but cannot get it to work in the main program I need it in. I will limit the program down to where I think error is occurring.
Problem: I pass in same value into function findStats(std::string sString) but get different results.
Case I:
stats = findStats("^9dff9d[Attribute 0% Active Defense 0]\r^f2f3f2Mana: 1411 ^00ff00(+1975)\r^f2f3f2^9dff9d[Attribute 0% Active Mana 0]\r^f2f3f2^ffc000Fortify Level: 12/12\r^f2f3f2^006effIdentified Attribute: + 6% Crit Damage\rIdentified Attribute: + 6 Accuracy\r^f2f3f2^006eff^O053Sacrifice Elapse(6/8)\r^00ff00 ^O041Desollar's Shadow\rÌÌÌÌÌÌÌÌL«");
The above case will output correctly and stores \r offsets correctly.
Case II:
stats = findStats((std::string)((char*)&buffer));
Case II is the case I need to work and has the same value as above Case I at start of function findStats but offsets for \r Are not stored for w.e reason when sString has same value at start of function.
//Function that finds positioning of \r
void calc_z (std::string &s, std::vector<int> & z)
{
int len = s.size();
z.resize (len);
int l = 0, r = 0;
for (int i=1; i<len; ++i)
if (z[i-l]+i <= r)
z[i] = z[i-l];
else
{
l = i;
if (i > r) r = i;
for (z[i] = r-i; r<len; ++r, ++z[i])
if (s[r] != s[z[i]])
break;
--r;
}
}
std::vector<std::string> findStats(std::string sString){
//sString is exactly the same in value for both cases of stats at this point
int offSet = 0;
int sOffsets[100] = {};
std::vector<std::string> t1;
std::string main_string = sString;
std::string substring = "\r";
std::string working_string = substring + main_string;
std::vector<int> z;
calc_z(working_string, z);
for(int i = substring.size(); i < working_string.size(); ++i){
if(z[i] >=substring.size()){
sOffsets[offSet] = i;
offSet++;
}
}
.... code ....problem occurs right above offsets are not stored for \r
}
void main()
{
std::vector<std::string> stats;
std::string buffer[10];
...code...
...code to find string and store in buffer...
stats = findStats((std::string)((char*)&buffer));
//stats = findStats("^9dff9d[Attribute 0% Active Defense 0]\r^f2f3f2Mana: 1411 ^00ff00(+1975)\r^f2f3f2^9dff9d[Attribute 0% Active Mana 0]\r^f2f3f2^ffc000Fortify Level: 12/12\r^f2f3f2^006effIdentified Attribute: + 6% Crit Damage\rIdentified Attribute: + 6 Accuracy\r^f2f3f2^006eff^O053Sacrifice Elapse(6/8)\r^00ff00 ^O041Desollar's Shadow\rÌÌÌÌÌÌÌÌL«");
for( std::vector<std::string>::const_iterator i = stats.begin(); i != stats.end(); ++i)std::cout << *i << ' ' << std::endl;
std::cin.get();
}

Answer 1

This statement: (std::string)((char*)&buffer) does not do what you think it does.
std::vector is not a simple array.
If you take address of std::vector, that won't be the address of the first element within std::vector.
YOu can't just cast const char* or char* into std::string. You can, however, construct new std::string using provided const char* or char * c-style string. const char *str = asdf; std::string s = std::string(str);.
So, to summarize:
If you want to pass several strings at once in std::vector, pass the buffer by const reference
typedef std::vector<std::string> StringVector;
void test(const StringVector& v){
for (StringVector::const_iterator i = v.begin(); i != v.end(); i++)
std::cout << *i << std::endl;
}
...
StringVector strings;
test(strings);
If you want to WRITE something into std::vector, pass it by reference:
typedef std::vector<std::string> StringVector;
void test(const StringVector& out){
out.push_back("test");
}
...
StringVector strings;
test(strings);
If you want to pass a single string from, vector, just pass the element itself (by reference, const reference, or by value, depending on what you want to do with it), without casts.
typedef std::vector<std::string> StringVector;
void test(const std::string& s){
std::cout << s << std::endl;
}
...
StringVector strings;
strings.push_back("test");
test(strings[0]);
--edit--
IN addition to that:
std::vector<std::string> findStats(std::string sString){
//sString is exactly the same in value for both cases of stats at this point
int offSet = 0;
int sOffsets[100] = {};//<<here's a problem
Using array with fixed size in this case is a bad idea. Your array is small, and it WILL overflow on any string larger than 100 bytes, breaking/crashing your program. You can simply store results on std::vectro<std::string>, make vector of structs, or use std::map, depending on your goals.