vim vertical line at 80 characters

#include <stdio.h>

#define MAX_LINE_LENGTH 80

int main() {
    int c;
    int char_count = 0;

    while ((c = getchar()) != EOF) {
        if (c == '\n') {
            char_count = 0;
            putchar(c);
        } else {
            putchar(c);
            char_count++;
            if (char_count == MAX_LINE_LENGTH) {
                putchar('\n');
                char_count = 0;
            }
        }
    }

    return 0;
}