嘗試分配內存使用malloc自定義結構時出錯

Question

我正試圖爲我的C程序中的自定義堆棧分配一些動態內存。但是，我收到錯誤0xC0000005：在malloc調用期間寫入位置0x00000014訪問衝突。

這裏是我的結構定義和我的函數調用malloc：

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

#define EMPTY -1; 

typedef enum boolean_tag { TRUE, FALSE } Boolean; 
typedef enum direction_tag { ACROSS, DOWN } AnswerDirection; /*The direction of an answer in the crossword*/ 

typedef struct answer_tag { 
    /*A single 'Answer' is a single node making up a linked list*/ 
    int answerNumber; 
    AnswerDirection direction; 
    char *answerString;   /*The answer's value in chars*/ 
    struct answer_tag *nextAnswer;  /*Points to the next answer in the linked list*/ 
} Answer; 

typedef struct space_tag { 
    /*A single space inside of a board*/ 
    int numberOfCurrentAnswers; /*How many Answers currently cross through the space*/ 
    char value; 
    int x; 
    int y; 
    struct space_tag *behindSpace; 
    struct space_tag *nextSpace; 
} Space; 

    void InitAnswers(Answer *); 
    Space *InitCrossword(); 
    Space *InitSpace(); 
    void ProgramClosingCleaning(Space *); 

main(){ 
Space *board; 
board = InitCrossword(); 
ProgramClosingCleaning(board); 
} 

void InitAnswers(Answer *answerKey){ 

} 

Space *InitCrossword(){ 
int xLimit, yLimit;   /*Limits set*/ 
int xTraverse, yTraverse; /*Coordinate variables to use in traversing*/ 
Space *currentSpace = NULL; 
Space *nextSpace;   
printf("Please enter the size of the board: x y\n"); 
scanf("%d %d", &xLimit, &yLimit); 
for (xTraverse = 0; xTraverse < xLimit; xTraverse++){ 
    for (yTraverse = 0; yTraverse < yLimit; yTraverse++){ 
     nextSpace = InitSpace(); 
     nextSpace->x = xTraverse; 
     nextSpace->y = yTraverse; 
     nextSpace->numberOfCurrentAnswers = 0; 
     nextSpace->value = EMPTY; 
     nextSpace->behindSpace = currentSpace; 
     currentSpace->nextSpace = nextSpace; 
     currentSpace = nextSpace; 
    } 
} 
while (currentSpace->behindSpace != NULL) 
    currentSpace = currentSpace->behindSpace; 
return currentSpace; 
} 

Space *InitSpace(){ 
return (Space *) malloc(sizeof(Space)); 
} 

void ProgramClosingCleaning(Space *currentSpace){ 
Space *nextSpace; 
while (currentSpace != NULL){ 
    nextSpace = currentSpace->nextSpace; 
    free(currentSpace); 
    } 
} 

感謝您的幫助！

Answer 1

返回功能我看到兩個問題發佈代碼（編譯器應該這已發出警告）：

• Implicit declarati Init()和InitSpace()這意味着他們將有一個返回類型int
• Init()不會返回一個值。

---

問題是這樣的線路在InitCrossword()功能：

currentSpace->nextSpace = nextSpace; 

在forcurrentSpace環是NULL的第一次迭代。

Answer 2

我很確定你使用的語法創建了類型爲space_tag和Space的結構實際上是一個變量（請參閱http://www.cplusplus.com/doc/tutorial/structures/）。

試試這個代碼：

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

typedef struct Space { 
    int numberOfCurrentAnswers; 
    char value; 
    int x; 
    int y; 
    struct Space *lastSpace; 
    struct Space *nextSpace; 
}; 

main(){ 
    struct Space *space; 
    space = Init(); 
} 

Space *Init(){ 
    struct Space *nextSpace; 
    nextSpace = InitSpace(); 
} 

Space *InitSpace(){ 
    return (Space *) malloc(sizeof(Space)); 
} 

編輯基於示例代碼發佈

Answer 3

你缺少在Init();