Question

我需要检查输入是否为＃34;插入WORD＆＃34;其中WORD是由小写英文字母组成的非空字符串。此外，最后和单词之间可以有多个空格。我遇到了分段错误，我不知道为什么。这是代码：

void *checkInsert(char *word[100000]) {
  bool ok = true;
  char *w[100000];
  char *nsert = "nsert";
  char c;
  int i = 0;
  while (i < strlen(nsert) && (ok)) {
    printf("%c", nsert[i]);
    c = getchar();
    if (nsert[i] != c) ok = false;
    ++i;
  }
  c = getchar();
  if ((ok) && (c == ' ')) {
    while (c == ' ') c = getchar();
  }
  else ok = false;
  i = 0;
  while (!isspace(c) && (ok)) {
    if (islower(c) != 0) {
      *w[i] = c;
      c = getchar();
      ++i;  
    } else if (c != '\n') ok = false;
  }
  if (ok) {
    while ((c != '\n') && (ok)) {
      c = getchar();
      if (c != ' ') ok = false;
    }
  }
  if (ok) word = w;
  else word = NULL;
}

Answer 1

这里有一个快速编写解析空格<word>空格<word>

#include <string.h>                                                            
#include <stdio.h>                                                             


#define FIRST "insert"                                                         

main(void) {                                                                   
    char c;                                                                    
    char *p;                                                                   
    char word[BUFSIZ];                                                         
    memset(word, 0, sizeof(word));                                             


    for (c = getchar(); isspace(c); c = getchar()){}                           
    p = FIRST;                                                                 
    while (*p) {                                                               
        if (*p++ != c) {                                                       
            return ;                                                           
        }                                                                      
        c = getchar();                                                         
    }                                                                          
    for (; isspace(c); c = getchar()){}                                        
    p = word;                                                                  
    while (!isspace(c)  && p - word < sizeof(word) - 1) {                                                      
        *p++ = c;                                                              
        c = getchar();                                                         
    }                                                                          
    printf("%s\n", word);                                                      
}

一些测试

/a.out 
insert otot
otot
aurel@fat:~/dev/test$ ./a.out 
sdf qsdf
aurel@fat:~/dev/test$ ./a.out 
inserttoto
toto
aurel@fat:~/dev/test$ ./a.out 
  insert  retezr 
retezr
aurel@fat:~/dev/test$ ./a.out 
  insert toto tutu
toto

使用专用的解析功能

#include <string.h>                                                            
#include <stdio.h>                                                             


#define FIRST "insert"                                                         



void parse(char *word, size_t size) {                                          
    char c;                                                                    
    char *p;                                                                   

    for (c = getchar(); isspace(c); c = getchar()){}                           
    p = FIRST;                                                                 
    while (*p) {                                                               
        if (*p++ != c) {                                                       
            return ;                                                           
        }                                                                      
        c = getchar();                                                         
    }                                                                          
    for (; isspace(c); c = getchar()){}                                        
    p = word;                                                                  
    while (!isspace(c) && p - word < size - 1) {                               
        *p++ = c;                                                              
        c = getchar();                                                         
    }                                                                          
    printf("%s\n", word);                                                      

}                                                                              


main(void) {                                                                   
    char word[BUFSIZ];                                                         
    memset(word, 0, sizeof(word));                                             

    parse(word, sizeof(word));                                                 
}

在C中读取输入时出现分段错误

1 个答案: