Extract words from an article

#include <iostream>

using namespace std;

#define ALPHA true
#define MISC false

char toLower(char ch)
{
    if (ch >= 'A' && ch <= 'Z') {
        return ch - 'A' + 'a';
    } else {
        return ch;
    }
}

bool isAlpha(char ch)
{
    return (ch >= 'a' && ch <= 'z') || ch == '\'';
}

int main()
{
    char words[256][80] = { '\0' };

    int idx = -1;
    int cursor = 0;
    char buf;
    bool state = MISC;

    while (cin.get(buf) && buf != '@') {
        char ch = toLower(buf);
        if (isAlpha(ch)) {
            if (state == MISC) {
                idx++;
            }
            state = ALPHA;
            words[idx][cursor] = ch;
            cursor++;
        } else {
            state = MISC;
            cursor = 0;
        }
    }

    for (int i = 0; i <= idx; i++) {
        cout << words[i] << endl;
    }
}