Finding item in string and say WHEN it was found - c++ - c++

Question

I have a string of items (see code). I want to say when a specific item from that list is found. In my example I want the output to be 3 since the item is found after the first two items. I can print out the separate items to the console but I cannot figure out how to do a count on these two items. I think it is because of the while loop... I always get numbers like 11 instead of two separate 1s. Any tips? :)
#include <iostream>
#include <string>
using namespace std;
int main() {
string items = "box,cat,dog,cat";
string delim = ",";
size_t pos = 0;
string token;
string item1 = "dog";
int count = 0;
`;
while ((pos = items.find(delim)) != string::npos)
{
token = items.substr(0, pos);
if (token != item1)
{
cout << token << endl; //here I would like to increment count for every
//item before item1 (dog) is found
items.erase(0, pos + 1);
}
else if (token == item1)
return 0;
}
return 0; //output: box cat
}

Answer 1

I replaced your search algorithm with the method explode, that separates your string by a delimiter and returns a vector, which is better suited for searching and getting the element count:
#include <string>
#include <vector>
#include <sstream>
#include <iostream>
#include <algorithm>
std::vector<std::string> explode(const std::string& s, char delim)
{
std::vector<std::string> result;
std::istringstream iss(s);
for (std::string token; std::getline(iss, token, delim); )
{
result.push_back(std::move(token));
}
return result;
}
int main()
{
std::string items = "box,cat,dog,cat";
std::string item1 = "dog";
char delim = ',';
auto resultVec = explode(items, delim);
auto itResult = std::find_if(resultVec.begin(), resultVec.end()
, [&item1](const auto& resultString)
{
return item1 == resultString;
});
if (itResult != resultVec.end())
{
auto index(std::distance(resultVec.begin(), itResult) + 1); // index is zero based
std::cout << index;
}
return 0;
}
By using std::find_if you can get the position of item1 by iterator, which you can use with std::distance to get the count of elements that are in front of it.
Credits for the explode method go to this post: Is there an equivalent in C++ of PHP's explode() function?

Answer 2

There are many ways to Rome. Here an additional solution using a std::regex.
But main approach is the same as the accepted answer. Using modern C++17 language elements, it is a little bit more compact.
#include <iostream>
#include <string>
#include <regex>
#include <iterator>
#include <vector>
const std::regex re{ "," };
int main() {
std::string items{ "box,cat,dog,cat" };
// Split String and put all sub-items in a vector
std::vector subItems(std::sregex_token_iterator(items.begin(), items.end(), re, -1), {});
// Search and check if found and show result
if (auto it = std::find(subItems.begin(), subItems.end(), "dog"); it != subItems.end())
std::cout << "Found at position: " << std::distance(subItems.begin(), it) + 1 << '\n';
else
std::cout << "Not found.\n";
return 0;
}