为什么赋值给一个int指针，什么时候我的C程序崩溃？ [英] Why does my C program crash when assigning a value to an int pointer?

问题描述

我想有一个函数从我的main（）函数传递一些整数指针和值分配给他们。然而，我的程序赋值时崩溃。这里是我的code：

  INT computeMoveLocation为（int * R，为int * C，字符*板）
{
    //一些code在这里
    * R = 0; //这破坏了程序
    * C = 0;
}
 

我并不想改变的地址的指针 - 我试图改变的值的整数的被指出。不过，我显然是做错了。

任何帮助将大大AP preciated。

编辑：
下面是主要的相关code（）。请让我知道我是否应该包括其他任何东西为好。

  INT的main（）
{
    //初始化code
    // ...    而（1）
    {        开关（MACHINE_STATE）
        {
            案例COMPUTER_MOVE：
            {
               //检查行的三个X
               //检查列三个X
               //检查对角线为三个X
               //否则，将其他地方
               INT * R，* C;
               computeMoveLocation（R，C，板）;
               computerMove（* R * C，板）;
               preVIOUS_STATE = COMPUTER_MOVE;
               MACHINE_STATE = HUMAN_MOVE;
               打破;
            }            //其他情况
        } //结束开关
    } //结束时
} //主到底
 

解决方案

正在传递的指针，但你没有分配内存。因此，他们在内存中的一个随机位置指向。

  INT computeMoveLocation为（int * R，为int * C，字符*板）
{
    //一些code在这里
    * R = 0; //这破坏了程序
    * C = 0;
}
 

坏主：

  INT的main（）
{
    INT * R;
    INT * C;
    字符*板;
    //糟糕，传递指针，但没有分配内存
    computeMoveLocation（R，C，板）;
    返回0;
}
 

好主＃1：

  INT的main（）
{
    INT R = 5;
    INT C = 5;
    炭板='A';
    //精致，传递对堆栈变量的地址
    computeMoveLocation（安培; R，和C，和放大器;板）;
    返回0;
}
 

好主＃2：

  INT的main（）
{
    为int * R =的malloc（sizeof的（INT））;
    * R = 5;
    INT * C =的malloc（sizeof的（INT））;
    * C = 5;
    字符*板=的malloc（sizeof的（炭））;
    *板='A';
    //精细，传递指针指向堆
    computeMoveLocation（R，C，板）;    免费（R）;
    免费（C）
    免费（板）;
    返回0;
}
 

I am trying to have a function take some integer pointers passed from my main() function and assign values to them. However, my program crashes when assigning values. Here is my code:

int computeMoveLocation(int* r, int* c, char* board)
{
    //some code up here
    *r = 0;    //This breaks the program
    *c = 0;
}

I'm not trying to change the address of the pointer--I'm trying to change the value of the integer being pointed to. However, I am apparently doing something wrong.

Any help would be greatly appreciated.

EDIT: Here is the relevant code from main(). Please let me know if I should include anything else as well.

int main()
{
    //initialization code
    //...

    while (1)
    {

        switch (MACHINE_STATE)
        {
            case COMPUTER_MOVE :
            {
               //check rows for three Xs
               //check columns for three Xs
               //check diagonals for three Xs
               //otherwise, move anywhere else
               int *r, *c;
               computeMoveLocation(r, c, board);
               computerMove(*r,*c, board);
               PREVIOUS_STATE = COMPUTER_MOVE;
               MACHINE_STATE = HUMAN_MOVE;
               break;
            }

            //Other cases
        }//end switch
    }//end while
}//end main

解决方案

You are passing in pointers but you didn't allocate memory. So they are pointing at a random location in memory.

int computeMoveLocation(int* r, int* c, char* board)
{
    //some code up here
    *r = 0;    //This breaks the program
    *c = 0;
}

Bad main :

int main()
{
    int *r;
    int *c;
    char *board;
    // bad, passing in pointers but didn't allocate memory
    computeMoveLocation(r, c, board); 
    return 0;
}

Good main #1:

int main()
{
    int r = 5;
    int c = 5;
    char board = 'a';
    // fine, passing address of variables on stack
    computeMoveLocation(&r, &c, &board); 
    return 0;
}

Good main #2:

int main()
{
    int *r = malloc(sizeof(int));
    *r = 5;
    int *c = malloc(sizeof(int));
    *c = 5;
    char *board = malloc(sizeof(char));
    *board = 'a';
    // fine, passing pointers that point to heap
    computeMoveLocation(r, c, board); 

    free(r);
    free(c)
    free(board);
    return 0;
}

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