C - 數組內容交換

Question

我實際上正在嘗試使用雙維數組的字符串（它實際上可能是三維的），以交換數組的兩個「單元」。

之前，我用的memcpy但是當談到長字符串，來執行時間長，所以我認爲這是可能簡單地交換陣列的指針，但我不知道該怎麼辦:(

這裏是我的代碼：

#include <stdio.h> 
#include <stdlib.h> 

void fonction(unsigned char*** tab); 

int main() 
{ 
    unsigned char*** tab; 
    tab = malloc(sizeof(unsigned char**) * 3); 
    if (tab == NULL) 
     exit(0); 

    for (int line = 0; line < 3; line++) 
     tab[line] = malloc(sizeof(unsigned char*) * 3); 

    for (int line = 0; line < 3; line++) 
     for (int column = 0; column < 3; column++) 
      tab[line][column] = malloc(sizeof(unsigned char) * 5); 


    for (int line = 0; line < 3; line++) 
     for (int column = 0; column < 3; column++) 
      for (int cell = 0;cell < 5;cell++) 
       tab[line][column][cell] = line * 3 * 5 + column * 5 + cell; 



    for (int i = 0;i < 32;i++) 
     fonction(tab); 

    for (int line = 0; line < 3; line++) 
     for (int column = 0; column < 3; column++) 
      free(tab[line][column]); 

    for (int line = 0; line < 3; line++) 
     free(tab[line]); 

    free(tab); 

    return 0; 
} 

void fonction(unsigned char*** tab) 
{ 
    unsigned char temp[5] = { 0, 0, 0, 0, 0 }; 

    int alea = 0; 
    int alea2 = 0; 
    int alea3 = 0; 
    int alea4 = 0; 

    srand(58); 

    for (int line = 0; line < 3; line++) 
    { 
     for (int column = 0; column < 3; column++) 
     { 
      alea = rand() % 3; 
      alea2 = rand() % 3; 
      alea3 = rand() % 3; 
      alea4 = rand() % 3; 

      *temp = tab[alea][alea2]; 
      tab[alea][alea2] = tab[alea3][alea4]; 
      tab[alea3][alea4] = *temp; 
     } 
    } 
} 

錯誤來釋放標籤時，這是可預期的，因爲fonction做任何舊事物:)

提前感謝！

Answer 1

我不知道爲什麼你正在使用

unsigned char temp[5] = { 0, 0, 0, 0, 0 }; 

只需使用

char* temp; 

，並做交換爲

 temp = tab[alea][alea2]; 
     tab[alea][alea2] = tab[alea3][alea4]; 
     tab[alea3][alea4] = temp; 

Answer 2

我不能真正得到什麼你想用你的代碼，這樣做，但這裏的走動字符串指針的工作示例：

#include <stdio.h> 
#include <stdlib.h> 

#define STR_NUM 3 

int main(void) 
{ 
    char * str1[STR_NUM] = {"one", "two", "three"}; 
    char * str2[STR_NUM]; 

    int i; 
    for (i = 0; i < STR_NUM; ++i) 
     puts(str1[i]); 

    for (i = 0; i < STR_NUM; ++i) 
     str2[i] = str1[i]; 

    for (i = 0; i < STR_NUM; ++i) 
     puts(str2[i]); 

    return 0; 
}