C++ While loop scoping issue - c++

Question

I recently started learning C++, and I'm currently trying build a tool that I recently built in python. My issue is that I can't figure out how I can make the length of the list of words global for example:
#include <iostream>
#include <fstream>
#include <string>
int main(int argc, char* argv[]) {
....
fstream file;
file.open(argv[i], ios::in);
if (file.is_open()) {
string tp;
while (getline(file, tp)) {
// cout << tp << "\n" << endl;
string words[] = {tp};
int word_count = sizeof(words) / sizeof(words[0]);
for (int e = 0; e < word_count; e++) {
cout << word_count[e];
}
}
file.close();
} else {
cout << "E: File / Directory " << argv[i] << " Does not exist";
return 0;
}
....
}
Where it says int word_count = sizeof(words) / sizeof(words[0]); and tring words[] = {tp};, I want to be able to use that globaly so that I can then later use then length of the array and the array itself later on so that I can loop through it and use them in another statement.
Can someone tell me how to do so?
And by the way, I've only been doing C++ for about 4 days so please dont get annoyed if I don't understand what you tell me.

Answer 1

string words[] = {tp}; creates an array with one element in it, the whole line. The name words implies that you instead want to store the individual words. The scope is also wrong if you want to use it after the loop is done. You need to declare it before the loop. Use a std::vector<std::string> to store the words. It could look like this:
#include <vector>
int main(int argc, char* argv[]) {
std::vector<std::string> words;
// ...
if (file) {
std::string word;
while (file >> word) { // read one word
words.push_back(word); // store it in the vector<string>
}
std::cout << "word count: " << words.size() << '\n';
// print all the words in the vector:
for(std::string& word : words) {
std::cout << word << '\n';
}
// file.close() // not needed, it'll close automatically when it goes out of scope
}

Answer 2

You have a number of issues here. First, rather than adding tp to an array called words on each iteration of the loop, you're actually creating a new array words and assigning tp to the first element of the array. words is destroyed at the end of each iteration of the while loop, but even if it wasn't, the {tp} expression would overwrite whatever was already in the array. Your line to calculate the length will therefore always calculate the length as 1.
Next, word_count[e] is trying to read element e of an array called word_count, but word_count is actually an integer. I'd be surprised if this actually compiled.
First I'd recommend you use a std::vector, and then if you just increase its scope to outside the loop then you can use it elsewhere. For example:
#include <iostream>
#include <fstream>
#include <string>
#include <vector>
int main(int argc, char* argv[]) {
fstream file;
file.open(argv[i], ios::in);
std::vector<std::string> words;
if (file.is_open()) {
string tp;
while (getline(file, tp)) {
words.push_back(tp); // Add tp to the vector of words
}
int word_count = words.size(); // vectors 'know' their own size.
for (int e = 0; e < word_count; e++) {
cout << words[e];
}
file.close();
} else {
cout << "E: File / Directory " << argv[i] << " Does not exist";
return 0;
}
}
// You can now use words as you please, because it is still in scope.
}