关于字典的程序，可以在字典中增加单词，每个单词可以有最多10个翻译，可以从字典中删除单词。这个程序的特点就是使用malloc操作内存。大家知道C语言中操作内存是很高效但很危险的，很容易出现内存泄露（memory leak).这个程序需要用struc来在内存中建立结构。如果要练习对内存进行操作和struc的使用，这个程序是非常好的练习题目。最后，我使用unix下的内存检测工具来检查是否存在错误的内存操作。好的程序是能够合理的尽量节约的使用内存，所以这个程序限制了内存的最大使用量。
这个程序我认为我写的不错，有参考价值。
如需要此程序的原说明文档和test case以及内存检测工具的使用方法，请与我联系。
Write an ANSI-C dictionary that allows other services to access a database of words and their translations as well as allows for additions and deletions to the dictionary. As between most languages, each word can have multiple translations.
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "a2.h"
#define LOOP 1 /* continue the loop */
void free_wordlist(wordlist *head); /* function declaration, free all allocated memory. Not include buffer */
int main(void)
{
int begin = 1; /* at the beginning of the wordlist (no word in the list) */
wordlist *head, *prev; /* beginning of the wordlist and the previous word */
prev = head = NULL;
char com1[] = "add"; /* command "add" */
char com2[] = "delete"; /* command "delete" */
char com3[] = "find"; /* command "find" */
char com4[] = "reverse"; /* command "reverse" */
char *buff; /* buffer used for reading words */
buff = (char *)malloc(2001); /* allocate memory */
if(buff == NULL) /* check if the program runs out of memory */
{
printf("out of memory\n");
exit(1);
}
while(LOOP)
{
char *str; /* a string used for saving command word */
scanf("%s", buff); /* read string into buffer */
str = (char *)malloc(strlen(buff) + 1); /* allocate memory */
if(str == NULL) /* chech if the program runs out of memory */
{
printf("out of memory\n");
free_wordlist(head); /* free all allocated memory, not include buffer */
free(buff); /* free allocated memory of buffer */
exit(1); /* exit the program */
}
strcpy(str, buff); /* copy the word from buffer */
if(!strcmp(str, com1)) /* command "add" */
{
char *w, *t; /* two strings used for saving words */
scanf("%s", buff); /* read word into buffer */
w = (char *)malloc(strlen(buff) + 1); /* allocate memory */
if(w == NULL) /* check if the program runs out of memory */
{
printf("out of memory\n");
free_wordlist(head); /* free all allocated memory, not include buffer */
free(str); /* free allocated memory of str */
free(buff);
exit(1);
}
strcpy(w, buff); /* copy word from buffer */
scanf("%s", buff); /* read the translation of the word */
t = (char *)malloc(strlen(buff) + 1);
if(t == NULL)
{
printf("out of memory\n");
free_wordlist(head);
free(w);
free(str);
free(buff);
exit(1);
}
strcpy(t, buff); /* copy from buffer */
if (begin) /* empty word list */
{
head = (wordlist *)malloc(sizeof(wordlist)); /* allocate memory for a word */
if(head == NULL) /* check if the program runs out of memory */
{
printf("out of memory\n");
free_wordlist(head); /* free the word list */
free(t);
free(w);
free(str);
free(buff);
exit(1);
}
head->word = (char *)malloc(strlen(w) + 1); /* allocate memory for the name of word */
if(head->word == NULL)
{
printf("out of memory\n");
free_wordlist(head);
free(t);
free(w);
free(str);
free(buff);
exit(1);
}
strcpy(head->word, w);
head->num_translations = 0; /* initialize the number of translations */
/* allocate memory for the translation of the word */
head->translation[head->num_translations] = (char *)malloc(strlen(t) + 1);
if(head->translation[head->num_translations] == NULL)
{
printf("out of memory\n");
free_wordlist(head);
free(t);
free(w);
free(str);
free(buff);
exit(1);
}
strcpy(head->translation[head->num_translations], t);
head->num_translations++; /* the number of translations increase */
head->next = NULL; /* set the next word NULL */
prev = head; /* set the previous word to head */
begin = 0; /* the word list is not empty */
}
else /* not empty word list */
{
int new = 1; /* new word */
wordlist *current;
wordlist *l;
for(l = head; l != NULL; l = l->next) /* check if it is new word */
{
if (strcmp(l->word, w) == 0)
{
current = l;
new = 0; /* is not new word */
break;
}
}
if(new == 1) /* it is new word */
{
/* allocate memory for new word */
current = (wordlist *)malloc(sizeof(wordlist));
if(current == NULL) /* program runs out of memory */
{
printf("out of memory\n");
free_wordlist(head); /* free the word list */
free(t);
free(w);
free(str);
free(buff);
exit(1);
}
current->num_translations = 0; /* initialize the number of translations */
current->word = (char *)malloc(strlen(w) + 1); /* allocate memory for the name of word */
if(current->word == NULL)
{
printf("out of memory\n");
free_wordlist(head);
free(t);
free(w);
free(str);
free(buff);
exit(1);
}
strcpy(current->word, w); /* copy word from w */
}
if(current->num_translations < 10) /* 10 translations at most */
{
int i, same;
same = 0; /* initialize to not exits */
/* check if the translation exits */
for(i = 0; i < current->num_translations; i++)
{
if(!strcmp(current->translation[i], t))
same = 1;
}
/* not exits */
if(!same)
{
/* allocate memory for the translation of word */
current->translation[current->num_translations] = (char *)malloc(strlen(t) + 1);
if(current->translation[current->num_translations] == NULL)
{
printf("out of memory\n");
free_wordlist(head);
free(t);
free(w);
free(str);
free(buff);
exit(1);
}
strcpy(current->translation[current->num_translations], t);
current->num_translations++;
}
}
if(new == 1) /* if the word is new */
{
current->next = NULL;
prev->next = current; /* connect this word to the previous word */
prev = current;
}
begin = 0; /* word list is not empty */
}
free(w); /* free allocated memory of "w" */
free(t); /* free allocated memory of "t" */
}
else if(!strcmp(str, com2)) /* command delete */
{
char *w; /* string used for saving word */
wordlist *l, *p;
scanf("%s", buff); /* read word into buffer */
w = (char *)malloc(strlen(buff) + 1); /* allocate memory for "w" */
if(w == NULL) /* check if the program runs out of memory */
{
printf("out of memory\n");
free_wordlist(head);
free(str);
free(buff);
exit(1);
}
strcpy(w, buff); /* copy word from buffer */
/* find word. p is the previous word */
p = l;
int i;
for(i = 0, l = head; l != NULL; l = l->next, i++)
{
if (strcmp(l->word, w) == 0)
break;
p = l;
}
if(l == NULL) /* nothing can be deleted */
;
else if(i == 0) /* deleting the first element */
{
/* free translations */
int x;
for(x = 0; x < head->num_translations; x++)
free(head->translation[x]);
if(head->next == NULL) /* deleting the first element, which is also the last */
{
begin = 1;
free(head->word);
free(head);
head = NULL;
}
else /* deleting the first element, it is not the last */
{
wordlist *tmp = head->next;
free(head->word);
free(head);
head = tmp;
}
}
else /* the other words */
{
/* free translations */
int x;
for(x = 0; x < l->num_translations; x++)
free(l->translation[x]);
if(l->next == NULL) /* deleting the last word */
prev = p;
p->next = l->next;
free(l->word);
free(l);
}
free(w); /* free memory */
}
else if(!strcmp(str, com3)) /* command "find" */
{
char *w;
wordlist *l;
scanf("%s", buff); /* read word into buffer */
w = (char *)malloc(strlen(buff) + 1);
if(w == NULL)
{
printf("out of memory\n");
free_wordlist(head);
free(str);
free(buff);
exit(1);
}
strcpy(w, buff); /* copy word from buffer */
for(l = head; l != NULL; l = l->next) /* find word */
{
if (strcmp(l->word, w) == 0)
break;
}
if(l == NULL) /* can not find word */
printf("cannot find word\n");
else
{
int i;
/* print all the translations of the word */
for(i = 0; i < l->num_translations; i++)
{
printf("%s\n", l->translation[i]);
}
}
free(w); /* free allocated memory */
}
else if(!strcmp(str, com4)) /* command "reverse" */
{
char *t;
wordlist *l;
scanf("%s", buff); /* read word into buffer */
t = (char *)malloc(strlen(buff) + 1);
if(t == NULL)
{
printf("out of memory\n");
free_wordlist(head);
free(str);
free(buff);
exit(1);
}
strcpy(t, buff); /* copy word from buffer */
int found; /* find the word */
found = 0; /* initialize to not find */
for(l = head; l != NULL; l = l->next)
{
int i;
for(i = 0; i < l->num_translations; i++)
{
if (strcmp(l->translation[i], t) == 0)
{
printf("%s\n", l->word); /* print the word */
found = 1; /* find the word */
}
}
}
if(found == 0) /* can not find the word */
printf("cannot find word\n");
free(t); /* free allocated memory */
}
else /* EOF or other command */
{
free_wordlist(head); /* free alloacated memory of the word list */
free(str); /* free allocated memory of "str", which is used for saving command name */
free(buff); /* free allocated memory of buffer */
return 0;
}
buff[0] = '\0'; /* initialize buffer */
free(str); /* free allocated memory of "str", which is used for saving command name */
}
return 0;
}
/* free allocated memory of the word list function */
void free_wordlist(wordlist *head)
{
wordlist *l, *tmp;
for(l = head; l != NULL; l = tmp)
{
int i;
for(i = 0; i < l->num_translations; i++)
free(l->translation[i]); /* free allocated memory of the translations of the words */
free(l->word); /* free allocated memory of the word name */
tmp = l->next;
free(l);
/* free allocated memory of the word */
}
}
这个程序我认为我写的不错，有参考价值。
如需要此程序的原说明文档和test case以及内存检测工具的使用方法，请与我联系。
Write an ANSI-C dictionary that allows other services to access a database of words and their translations as well as allows for additions and deletions to the dictionary. As between most languages, each word can have multiple translations.
#include <stdio.h>#include <stdlib.h>#include <string.h>#include "a2.h"#define LOOP 1 /* continue the loop */void free_wordlist(wordlist *head); /* function declaration, free all allocated memory. Not include buffer */
int main(void){
int begin = 1; /* at the beginning of the wordlist (no word in the list) */
wordlist *head, *prev; /* beginning of the wordlist and the previous word */ prev = head = NULL; char com1[] = "add"; /* command "add" */ char com2[] = "delete"; /* command "delete" */ char com3[] = "find"; /* command "find" */ char com4[] = "reverse"; /* command "reverse" */ char *buff; /* buffer used for reading words */ buff = (char *)malloc(2001); /* allocate memory */ if(buff == NULL) /* check if the program runs out of memory */ { printf("out of memory\n"); exit(1); } while(LOOP) { char *str; /* a string used for saving command word */ scanf("%s", buff); /* read string into buffer */ str = (char *)malloc(strlen(buff) + 1); /* allocate memory */ if(str == NULL) /* chech if the program runs out of memory */ { printf("out of memory\n"); free_wordlist(head); /* free all allocated memory, not include buffer */ free(buff); /* free allocated memory of buffer */ exit(1); /* exit the program */ } strcpy(str, buff); /* copy the word from buffer */ if(!strcmp(str, com1)) /* command "add" */ { char *w, *t; /* two strings used for saving words */ scanf("%s", buff); /* read word into buffer */ w = (char *)malloc(strlen(buff) + 1); /* allocate memory */ if(w == NULL) /* check if the program runs out of memory */ { printf("out of memory\n"); free_wordlist(head); /* free all allocated memory, not include buffer */ free(str); /* free allocated memory of str */ free(buff); exit(1); } strcpy(w, buff); /* copy word from buffer */ scanf("%s", buff); /* read the translation of the word */ t = (char *)malloc(strlen(buff) + 1); if(t == NULL) { printf("out of memory\n"); free_wordlist(head); free(w); free(str); free(buff); exit(1); } strcpy(t, buff); /* copy from buffer */ if (begin) /* empty word list */ { head = (wordlist *)malloc(sizeof(wordlist)); /* allocate memory for a word */ if(head == NULL) /* check if the program runs out of memory */ { printf("out of memory\n"); free_wordlist(head); /* free the word list */ free(t); free(w); free(str); free(buff); exit(1); } head->word = (char *)malloc(strlen(w) + 1); /* allocate memory for the name of word */ if(head->word == NULL) { printf("out of memory\n"); free_wordlist(head); free(t); free(w); free(str); free(buff); exit(1); } strcpy(head->word, w); head->num_translations = 0; /* initialize the number of translations */ /* allocate memory for the translation of the word */ head->translation[head->num_translations] = (char *)malloc(strlen(t) + 1); if(head->translation[head->num_translations] == NULL) { printf("out of memory\n"); free_wordlist(head); free(t); free(w); free(str); free(buff); exit(1); } strcpy(head->translation[head->num_translations], t); head->num_translations++; /* the number of translations increase */ head->next = NULL; /* set the next word NULL */ prev = head; /* set the previous word to head */ begin = 0; /* the word list is not empty */ } else /* not empty word list */ { int new = 1; /* new word */ wordlist *current; wordlist *l; for(l = head; l != NULL; l = l->next) /* check if it is new word */ { if (strcmp(l->word, w) == 0) { current = l; new = 0; /* is not new word */ break; } } if(new == 1) /* it is new word */ { /* allocate memory for new word */ current = (wordlist *)malloc(sizeof(wordlist)); if(current == NULL) /* program runs out of memory */ { printf("out of memory\n"); free_wordlist(head); /* free the word list */ free(t); free(w); free(str); free(buff); exit(1); } current->num_translations = 0; /* initialize the number of translations */ current->word = (char *)malloc(strlen(w) + 1); /* allocate memory for the name of word */ if(current->word == NULL) { printf("out of memory\n"); free_wordlist(head); free(t); free(w); free(str); free(buff); exit(1); } strcpy(current->word, w); /* copy word from w */ } if(current->num_translations < 10) /* 10 translations at most */ { int i, same; same = 0; /* initialize to not exits */ /* check if the translation exits */ for(i = 0; i < current->num_translations; i++) { if(!strcmp(current->translation[i], t)) same = 1; } /* not exits */ if(!same) { /* allocate memory for the translation of word */ current->translation[current->num_translations] = (char *)malloc(strlen(t) + 1); if(current->translation[current->num_translations] == NULL) { printf("out of memory\n"); free_wordlist(head); free(t); free(w); free(str); free(buff); exit(1); } strcpy(current->translation[current->num_translations], t); current->num_translations++; } } if(new == 1) /* if the word is new */ { current->next = NULL; prev->next = current; /* connect this word to the previous word */ prev = current; } begin = 0; /* word list is not empty */ } free(w); /* free allocated memory of "w" */ free(t); /* free allocated memory of "t" */ } else if(!strcmp(str, com2)) /* command delete */ { char *w; /* string used for saving word */ wordlist *l, *p; scanf("%s", buff); /* read word into buffer */ w = (char *)malloc(strlen(buff) + 1); /* allocate memory for "w" */ if(w == NULL) /* check if the program runs out of memory */ { printf("out of memory\n"); free_wordlist(head); free(str); free(buff); exit(1); } strcpy(w, buff); /* copy word from buffer */ /* find word. p is the previous word */ p = l; int i; for(i = 0, l = head; l != NULL; l = l->next, i++) { if (strcmp(l->word, w) == 0) break; p = l; } if(l == NULL) /* nothing can be deleted */ ; else if(i == 0) /* deleting the first element */ { /* free translations */ int x; for(x = 0; x < head->num_translations; x++) free(head->translation[x]); if(head->next == NULL) /* deleting the first element, which is also the last */ { begin = 1; free(head->word); free(head); head = NULL; } else /* deleting the first element, it is not the last */ { wordlist *tmp = head->next; free(head->word); free(head); head = tmp; } } else /* the other words */ { /* free translations */ int x; for(x = 0; x < l->num_translations; x++) free(l->translation[x]); if(l->next == NULL) /* deleting the last word */ prev = p; p->next = l->next; free(l->word); free(l); } free(w); /* free memory */ } else if(!strcmp(str, com3)) /* command "find" */ { char *w; wordlist *l; scanf("%s", buff); /* read word into buffer */ w = (char *)malloc(strlen(buff) + 1); if(w == NULL) { printf("out of memory\n"); free_wordlist(head); free(str); free(buff); exit(1); } strcpy(w, buff); /* copy word from buffer */ for(l = head; l != NULL; l = l->next) /* find word */ { if (strcmp(l->word, w) == 0) break; } if(l == NULL) /* can not find word */ printf("cannot find word\n"); else { int i; /* print all the translations of the word */ for(i = 0; i < l->num_translations; i++) { printf("%s\n", l->translation[i]); } } free(w); /* free allocated memory */ } else if(!strcmp(str, com4)) /* command "reverse" */ { char *t; wordlist *l; scanf("%s", buff); /* read word into buffer */ t = (char *)malloc(strlen(buff) + 1); if(t == NULL) { printf("out of memory\n"); free_wordlist(head); free(str); free(buff); exit(1); } strcpy(t, buff); /* copy word from buffer */ int found; /* find the word */ found = 0; /* initialize to not find */ for(l = head; l != NULL; l = l->next) { int i; for(i = 0; i < l->num_translations; i++) { if (strcmp(l->translation[i], t) == 0) { printf("%s\n", l->word); /* print the word */ found = 1; /* find the word */ } } } if(found == 0) /* can not find the word */ printf("cannot find word\n"); free(t); /* free allocated memory */ } else /* EOF or other command */ { free_wordlist(head); /* free alloacated memory of the word list */ free(str); /* free allocated memory of "str", which is used for saving command name */ free(buff); /* free allocated memory of buffer */ return 0; } buff[0] = '\0'; /* initialize buffer */ free(str); /* free allocated memory of "str", which is used for saving command name */ } return 0;}/* free allocated memory of the word list function */void free_wordlist(wordlist *head){ wordlist *l, *tmp; for(l = head; l != NULL; l = tmp) { int i; for(i = 0; i < l->num_translations; i++) free(l->translation[i]); /* free allocated memory of the translations of the words */ free(l->word); /* free allocated memory of the word name */ tmp = l->next; free(l); /* free allocated memory of the word */ }}
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