通过指针访问数组时出现分段错误

Question

我有一个全局数组声明为

int Team1[12][8];

当我调用该函数时

int readLineupB(int teamNr){

      int (*teamToRead)[12][8];
      teamToRead = &Team1;

      for (int currentPlayersNumber = 1; currentPlayersNumber<11; currentPlayersNumber++) {
        for (int otherNumber = 1; otherNumber<7; otherNumber++) {
            *teamToRead[currentPlayersNumber][otherNumber] = 20;
        }
    } 
    return 1;
}

它填充数组直到位置[10]，[3]，然后看似[10]，[4]我得到一个分段错误，我无法理解为什么。

Answer 1

检查数据类型。

teamToRead是一个指向int [12][8]数组的指针。

由于运算符优先级 ，下标运算符绑定高于解除引用。

所以，如果是的话

  *teamToRead[currentPlayersNumber][otherNumber] = 20;

你想说点什么

  *(* ( teamToRead + currentPlayersNumber ) ) [otherNumber] = 20;

其中，指针算术变为非法，因为它们遵守指针类型，从而冒险越界。

要解决这个问题，您需要通过明确的括号来强制执行取消引用的优先级，例如

 (*teamToRead)[currentPlayersNumber][otherNumber] = 20;

Answer 2

另一个选择是放弃指向二维数组的指针，只使用指向（一维数组）一维数组的指针：

int Team1[12][8];

int readLineupB(int teamNr){
    // declare teamToRead as a pointer to array of 8 ints
    int (*teamToRead)[8];

    // Team1 is of type int x[12][8] that readily decays 
    // to int (*x)[8]
    teamToRead = Team1;

    for (int currentPlayersNumber = 1; currentPlayersNumber<11; currentPlayersNumber++) {
        for (int otherNumber = 1; otherNumber<7; otherNumber++) {
            // no dereference here.
            teamToRead[currentPlayersNumber][otherNumber] = 20;
        }
    }
    return 0;
}