对输入的字符串中C关键词的查找统计。

#include <stdio.h> #include <ctype.h> #include <string.h>   #define MAXWORD 80   #define NKEYS (sizeof(keytab) / sizeof(struct key))   structkey {                             char*word;     intcount; }                          keytab[] = {                             "auto", 0,     "break", 0,     "case", 0,     "char", 0,     "const", 0,     "continue", 0,     "default", 0,     "do", 0,     "double", 0,     "else", 0,     "enum", 0,     "extern", 0,     "float", 0,     "for", 0,     "goto", 0,     "if", 0,     "int", 0,     "long", 0,     "register", 0,     "return", 0,     "short", 0,     "singed", 0,     "sizeof", 0,     "static", 0,     "struct", 0,     "switch", 0,     "typedef", 0,     "union", 0,     "unsigned", 0,     "void", 0,     "volatile", 0,     "while", 0 }                         ;   voidgetword(char*, int); intbinsearch(char*, structkey *, int);   intmain(intargc, char*argv[]) {                             intn;     charword[MAXWORD];       printf("本程序将为您统计C语言的关键字的个数，请输入，输入end结束输入：\n");     do     {                                 getword(word, MAXWORD);         if(isalpha(word[0]))         {                                     if((n = binsearch(word, keytab, NKEYS)) >= 0)             {                                         keytab[n].count++;//找到则对应次数+1             }         }       }     while(strcmp(word,"end") != 0);       printf("您的输入中C语言关键字出现的次数统计如下：\n");     for(n = 0; n < NKEYS; n++)     {                                 if(keytab[n].count > 0)         {                                     printf("%-10s: %6d\n", keytab[n].word, keytab[n].count);         }     }       return0; }                           /* 折半查找：在tab[0]到tab[n-1]中查找word */ intbinsearch(char*word, structkey tab[], intn) {                             intresult;     intlow, high, mid;       low = 0;     high = n - 1;     while(low <= high)     {                                 mid = (low + high) / 2;         if((result = strcmp(word, tab[mid].word)) < 0)         {                                     high = mid - 1;         }         elseif (result > 0)         {                                     low = mid + 1;         }         else         {                                     returnmid;         }     }     return-1; }                           /* getword：从输入中获取某个单词 */ voidgetword(char*word, intlim) {                             intc;     voidungetch(int);     char*w = word;       while(isspace(c = getchar()))     {                             }     if(c != EOF)     {                                 *w = c;         w++;     }     if(!isalpha(c))     {                                 *w = '\0';     }     for( ; --lim > 0; w++)     {                                 if(!isalnum(*w = getchar()))         {                                     //读入的某个字符不是字母，则将它退还给输入缓冲区             ungetch(*w);             break;         }     }     *w = '\0'; }