Basic C++ problems

Used [] instead of (), it seems to working better so far.

I'm running into another problem with my code.
(Different code, but it's part of the same assignment.)

Code:

#include <iostream>
#include <iomanip> // for fixed and setprecision
#include "assn.h" // for is_vowel function
using namespace std;

int main () {

    string wordfile;
    int wordcount;
    int lettercount = 0;
    //int size = wordfile.size();
    int sentencecount = 0;
    int i = 0;
    char ch = wordfile[i];
    while (cin >> wordfile) {
        ++wordcount;
        lettercount = lettercount + wordfile.size();
        
        if (ch == '?' || '.' || ';' || ':' || '!') {
            ++sentencecount;
            ++i;
        }
        
        else {
            ++i;
        }
        
    }
    
    cout << wordcount << endl;
    cout << lettercount << endl;
    cout << sentencecount << endl;
    

return 0;

}

What I'm trying to with this one is to determine the number of words, letters, and sentences there are in a document.
Words and letters works fine if there isn't any other code, but once I implement my code for sentence count, it starts to go wrong from there.

If I take out my code for sentence counting/displaying it, and run the program with text file that says "I like food.", it will display:
10
3
Which is what I want.
But if I include my sentence counting code in my program (see the code I posted above), I get:
64
10
3
I notice that the second and third values correctly display word count and letter count, but they're being displayed in the wrong position. Also, where did that 64 come from?
How is the code I have created for sentence counting affecting the other code?