代码如下：

#include <stdio.h>

#define MAXHIST 20 /* max length of histogram */
#define MAXWORD 11 /* max length of a word */
#define IN  1 /* inside a word */
#define OUT 0 /* outside a word */

int main() {
    int i, j, c, state, nc;
    int maxvalue; /* maximum value for wl[] */
    int ovflow; /* number of overflow words */
    int wl[MAXWORD]; /* word length counters */
    state = OUT;
    nc = 0; /* number of chars in a word */
    ovflow = 0; /* number of words >= MAXWORD */

    for ( i = 0; i < MAXWORD; i++ ) {
        wl[i] = 0;
    }

    while ( ( c = getchar() ) != EOF ) {
        if ( c == ' ' || c == '\t' || c == '\n' ) {
            state = OUT; /* 在单词外，标志着一个单词的结束 */

            if ( nc > 0 ) {
                if ( nc < MAXWORD ) {
                    ++wl[nc];
                } else {
                    ++ovflow;
                }

                nc = 0; /* 准备计数下一个单词的字符数 */
            }
        } else if ( state == OUT ) { /* 出现某个单词的首字符 */
            state = IN;
            nc = 1; /* beginning of a new word */
        } else { /* 单词除过首字符的其他字符 */
            ++nc; /* inside a word */
        }
    }

    maxvalue = 0; /* find the maximum value in wl[MAXWORD] */

    for ( i = 1; i < MAXWORD; i++ ) { /* wl[0]未使用(单词的长度大于0) */
        if ( wl[i] > maxvalue ) {
            maxvalue = wl[i];
        }
    }

    for ( i = MAXHIST; i > 0; i-- ) { /* 输出直方图(垂直) */
        for ( j = 1; j < MAXWORD; j++ ) {
            if ( wl[j] * MAXHIST / maxvalue >= i ) {
                printf ( " * " );
            } else {
                printf ( "   " );
            }
        }

        putchar ( '\n' );
    }

    for ( i = 1; i < MAXWORD; i++ ) {
        printf ( "%2d ", i );
    }

    putchar ( '\n' );

    for ( i = 1; i < MAXWORD; i++ ) {
        printf ( "%2d ", wl[i] );
    }

    putchar ( '\n' );

    if ( ovflow > 0 ) { /* 是否有长度超出最大单词长度的单词 */
        printf ( "There are %d words >= %d/n", ovflow, MAXWORD );
    }

    return 0;
}