>>577
1番
「文字数」は印字可能な文字(SPより後)の個数という意味にとった。

#include <stdio.h>
#include <stdbool.h>

void main() {
    int c, chars = 0, words = 0, sentences = 0;
    bool sp = false;
    while((c = getchar()) != EOF) {
        switch(c) {
            case '.':
            case '?':
            case '!':
                sentences++;
            case ',':
                chars++;
            case ' ':
                if(!sp) words++, sp = true;
                break;
            default:
                if(c > 0x20) chars++;
                sp = false;
        }
    }
    printf("%d %d %d\n", chars, words, sentences);
}