#include<stdio.h>

#define IN 1

#define OUT 0

main()

{

    int c, state;

    int nword;

    nword = ;

    state = OUT;

    while((c = getchar()) != EOF){

        if(c == ' ' || c == '\n' || c == '\t')

            state = OUT;

        else if(state == OUT){

            state = IN;

            ++ nword;

        }

    }    // 可以用集合里的Vn图理解, 每次循环都有三种情况。

    printf("%d\n", nword);

}

#include<stdio.h>

main()

{

    int c, i, nwhite, nother, ndigit[];

    nwhite = nother;

    for(i = ; i < ; i ++)

        ndigit[i] = ;

    while((c = getchar()) != EOF){

        switch(c){

            case '': case '': case '': case '': case '': case '': case '': case '': case '': case '':

                ndigit[c-''] ++;

                break;

            case ' ':

            case '\n':

            case '\t':

                nwhite ++;

                break;

            default:

                nother ++;

                break;

        }

    }

    printf("digits =");

    for(i = ; i < ; i ++)

        printf(" %d", ndigit[i]);

    printf(", white space = %d, other = %d\n", nwhite, nother);

    return ;

}

#include<stdio.h>

#define MAXLINE 1000

int getline(char line[], int max);

int strindex(char source[], char searchfor[]);

char pattern[] = "ould";

main()

{

    char line[MAXLINE];

    int found = ;

    while(getline(line , MAXLINE) > )

        if(strindex(line , pattern) >= ){

            printf("%s", line);

            found++;

        }

    return found;

}

int getline(char s[], int lim)

{

    int c, i;

    i = ;

    while(--lim >  && (c=getchar()) != EOF && c != '\n')

        s[i++] = c;

    if(c == '\n')

        s[i++] = c;

    s[i] = '\0';

    return i;

}

int strindex(char s[], char t[])

{

    int i, j, k;

    for(i = ; s[i] != '\0'; i ++){

        for(j=i, k=; t[k]!='\0' && s[j]==t[k]; j++, k++)

            ;

        if(k >  && t[k] == '\0')

            return i;

    }

    return -;

}