何时应在C中使用双间接寻址?谁能举例说明?
When should a double indirection be used in C? Can anyone explain with a example?
我所知道的是,双间接向是指向指针的指针.为什么我需要一个指向指针的指针?
What I know is that a double indirection is a pointer to a pointer. Why would I need a pointer to a pointer?
推荐答案如果您想要一个字符列表(一个单词),则可以使用char *word
If you want to have a list of characters (a word), you can use char *word
如果您想要单词列表(一个句子),则可以使用char **sentence
If you want a list of words (a sentence), you can use char **sentence
如果需要句子列表(独白),可以使用char ***monologue
If you want a list of sentences (a monologue), you can use char ***monologue
如果您想要独白(传记)列表,则可以使用char ****biography
If you want a list of monologues (a biography), you can use char ****biography
如果要获取传记列表(生物图书馆),可以使用char *****biolibrary
If you want a list of biographies (a bio-library), you can use char *****biolibrary
如果您要获取生物图书馆列表(大声笑),可以使用char ******lol
If you want a list of bio-libraries (a ??lol), you can use char ******lol
......
是的,我知道这些可能不是最好的数据结构
非常无聊的哈哈
#include <stdio.h> #include <stdlib.h> #include <string.h> int wordsinsentence(char **x) { int w = 0; while (*x) { w += 1; x++; } return w; } int wordsinmono(char ***x) { int w = 0; while (*x) { w += wordsinsentence(*x); x++; } return w; } int wordsinbio(char ****x) { int w = 0; while (*x) { w += wordsinmono(*x); x++; } return w; } int wordsinlib(char *****x) { int w = 0; while (*x) { w += wordsinbio(*x); x++; } return w; } int wordsinlol(char ******x) { int w = 0; while (*x) { w += wordsinlib(*x); x++; } return w; } int main(void) { char *word; char **sentence; char ***monologue; char ****biography; char *****biolibrary; char ******lol; //fill data structure word = malloc(4 * sizeof *word); // assume it worked strcpy(word, "foo"); sentence = malloc(4 * sizeof *sentence); // assume it worked sentence[0] = word; sentence[1] = word; sentence[2] = word; sentence[3] = NULL; monologue = malloc(4 * sizeof *monologue); // assume it worked monologue[0] = sentence; monologue[1] = sentence; monologue[2] = sentence; monologue[3] = NULL; biography = malloc(4 * sizeof *biography); // assume it worked biography[0] = monologue; biography[1] = monologue; biography[2] = monologue; biography[3] = NULL; biolibrary = malloc(4 * sizeof *biolibrary); // assume it worked biolibrary[0] = biography; biolibrary[1] = biography; biolibrary[2] = biography; biolibrary[3] = NULL; lol = malloc(4 * sizeof *lol); // assume it worked lol[0] = biolibrary; lol[1] = biolibrary; lol[2] = biolibrary; lol[3] = NULL; printf("total words in my lol: %d\n", wordsinlol(lol)); free(lol); free(biolibrary); free(biography); free(monologue); free(sentence); free(word); }输出:
total words in my lol: 243更多推荐
为什么要使用双重间接?或为什么使用指向指针的指针?
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