用C中的指针表达式迭代2D数组 [英] Iterating 2D array with pointer expressions in C

问题描述

我正在练习指针，并且想用指针操作代替数组来遍历数组的元素.我已经阅读了许多文章，无法理解这个概念.有人可以解释吗?

I'm practicing pointers and want to substitute pointer operations in place of the arrays to traverse through the elements of the array. I have read numerous articles and cannot grasp this concept. Can someone explain?

在这里，我制作了一个2D数组，并使用基本的嵌套for循环遍历它，但是想使用指针；

Here I made a 2D array and iterated through it using a basic nested for-loop, but want to use pointers;

int test[3][2] = {1,4,2,5,2,8};

for (int i = 0 ; i < 3; i++) {

    for (int j = 0; j < 2; j++) {

        printf("%d\n", test[i][j]);
    }
}

推荐答案

int test[3][2] = {{1,4},{2,5},{2,8}};

// Define a pointer to walk the rows of the 2D array.
int (*p1)[2] = test;

// Define a pointer to walk the columns of each row of the 2D array.
int *p2 = NULL;

// There are three rows in the 2D array.
// p1 has been initialized to point to the first row of the 2D array.
// Make sure the iteration stops after the third row of the 2D array.
for (; p1 != test+3; ++p1) {

    // Iterate over each column of the arrays.
    // p2 is initialized to *p1, which points to the first column.
    // Iteration must stop after two columns. Hence, the breaking
    // condition of the loop is when p2 == *p1+2
    for (p2 = *p1; p2 != *p1+2; ++p2 ) {
        printf("%d\n", *p2);
    }
}

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