C语言：使用指针访问二维数组失败，一维正常，求解决方法

Hey there! Let's figure out why your code isn't working with the 2D array pointer, and fix it step by step.

The Core Problem: Mismatched Pointer Types #

Your line char *temp = &test; is the culprit here. Let's break down the types:

• test is a 2D array of type char[2][4] (2 rows, each with 4 chars).
• &test gives you a pointer to this entire 2D array, which has the type char (*)[2][4] (read as "pointer to an array of 2 arrays of 4 chars").
• You're trying to assign this to a char* variable—these types are completely incompatible! When you do temp[1][2], the pointer arithmetic gets messed up because the compiler expects a char* to jump 1 byte per index, but your actual pointer points to a much larger structure.

In 1D arrays, you might have gotten away with temp = &test (though it's still technically incorrect), because the array name decays to a pointer to its first element, and the memory layout is linear. But 2D arrays add an extra layer of indirection that breaks this hack.

Fixes to Make It Work #

Here are two clean, correct ways to handle this:

1. Use the Exact Pointer Type for the 2D Array

Declare temp as a pointer to your 2D array type, then dereference it to access the array elements:

#include <stdio.h>

int main() { 
    char test[2][4] = {"BbBa","CBAD"} ; 
    char ch = 'A'; 
    char (*temp)[2][4] = &test; // Correct pointer type
    int i=0; 
    if ((*temp)[1][2] == ch){ // Dereference temp first to get the array
        printf("Yes"); 
    } else{ 
        printf("No."); 
    } 
    getchar(); 
    return 0; 
}

2. Use a Pointer to the Rows of the 2D Array

A 2D array can decay to a pointer to its first row (which is a char[4] array). So you can declare temp as a pointer to a 4-char array, which lets you use temp[row][col] directly:

#include <stdio.h>

int main() { 
    char test[2][4] = {"BbBa","CBAD"} ; 
    char ch = 'A'; 
    char (*temp)[4] = test; // Pointer to each 4-char row
    int i=0; 
    if (temp[1][2] == ch){ // Now this works as expected!
        printf("Yes"); 
    } else{ 
        printf("No."); 
    } 
    getchar(); 
    return 0; 
}

This is probably the more common approach because it lets you use the familiar [row][col] syntax without extra dereferencing.

Why This Works #

In the second fix, temp points to the first row of test. temp[1] jumps to the second row (since each row is 4 chars, it moves 4 bytes in memory), and temp[1][2] grabs the third character of that row—which is exactly 'A', so your code will print "Yes" as expected.

内容的提问来源于stack exchange，提问作者Cc Li