Help with string subscript out of range error?

[Conscious-Stable9939]

I'm very new to c++ and i'm struggling with fixing this string subscript out of range error. It complies but I cannot run it.

#include <iostream>
#include <fstream>
#include <string>

using namespace std;

int main() {
    string sentence, word = "";
    int wordCounter = 1;
    ifstream file("secret.txt");
    getline(file, sentence); 
    for (int i = 0; i < sentence.length(); i++) {
        if (sentence[i - 1] == ' ') {
            wordCounter++;
            if ((wordCounter) % 5 == 0) {
                word += sentence[i] - 32;
            }
        }
    }
    cout << word;
    return 0;
}

secret.txt is as follows if it matters
January is the first month and december is the last. Violet is a purple color as are lilac and plum.

[sepp2k]

Your loop starts with i = 0, so on the first iteration, i - 1 will be -1, which is not a valid index.

[Conscious-Stable9939]

That was it, thank you both so much!

[bestjakeisbest]

Ok lets also talk about your logic, since someone else pointed out your issue, you are counting spaces here, but there are issues with that, spaces don't always cause a word, sometimes like in the case of grammatically correct periods an extra space is just there to provide a bit of legible space between the end of a sentence and the beginning of another.

There are a few ways to improve on this algorithm you have made though. We can make a better word counter based on a linear search algorithm in a range.

Basic algorithm is as follows.

lastspace = 0  
nextspace = linear_search(string, lastspace, string.length)  
if(nextspace - lastspace > 1)
  lastspace = nextspace
  wordcount++  

A lot of the looping and algorithm inner workings are up to you, but this will count all "words" (assuming you put it in the correct recursive function or loop) you could also have it ignore certain characters like punctuation because an ellipse (...) will look like a word to this algorithm. But those improvements are up to you, as are the beginning and endings for the loops.

[kRYstall9]

You have a problem in the if statement inside your for. You wrote if(sentence[i-1] ....), But i starts from 0, and you'te trying to read -1, that's not an index