我有一个程序出现分段错误。该程序是一个魔方程序，要求用户输入正方形（矩阵）的大小，然后逐行询问正方形的数字。我使用指针指向 declareArray 函数中的数组，以引用它在主函数中声明的位置。我想保留指针以便练习使用它们，即使我知道我可以在没有指针的情况下使程序工作。我认为指针是这里的问题，但我找不到我做错了什么。
这是代码：
int main(void)
{
int *arr[SIZE][SIZE] = " ";
declareArray(&arr);
declareArray();
return 0;
}
//main logic
int declareArray(int *arr[SIZE][SIZE])
{
//variables
int rowNumber = 0;
int dimension = 0;
//int arr[SIZE][SIZE] = {0};
int row, col;
int sum, sum1, sum2;
int flag = 0;
//ask for input of squares
printf("Please enter the dimension of the square: ");
//makes sure the size is between 1 and 15 for the dimension of the square
if(scanf("%d", &dimension) != 1 || dimension >= 15 || dimension < 1)
{
printf("invalid inputn");
return 1;
}
//enter the data
//array rows
for(row = 0; row < dimension; ++row)
{
printf("Please enter the data for row %d: ", ++rowNumber);
//array columns
for(col = 0; col < dimension; ++col)
{
//store the user input
scanf("%2d", &*arr[row][col]);
}
}
printf("n");
printf("Here is the square");
printf("n");
//print the square
//array rows
for(row = 0; row < dimension; ++row)
{
//array columns
for(col = 0; col < dimension; ++col)
{
printf("%d", *arr[row][col]);
}
printf("n");
}
//Checks Sum of diagonal elements
sum = 0;
for (row = 0; row < dimension; row++) {
for (col = 0; col < dimension; col++) {
if (row == col)
sum = sum + *arr[row][col];
}
}
//Checks Sum of Rows
for (row = 0; row < dimension; row++) {
sum1 = 0;
for (col = 0; col < dimension; col++) {
sum1 = sum1 + *arr[row][col];
}
if (sum == sum1)
flag = 1;
else {
flag = 0;
break;
}
}
//Checks sum of Columns
for (row = 0; row < dimension; row++) {
sum2 = 0;
for (col = 0; col < dimension; col++) {
sum2 = sum2 + *arr[col][row];
}
if (sum == sum2)
flag = 1;
else {
flag = 0;
break;
}
}
//if the sums match, it will print a success message with the constant
//if the sums dont match, a fail message will appear
if (flag == 1)
printf("nTHE SQUARE IS A MAGIC SQUARE WITH A CONSTANT OF %d n", sum);
else
printf("nThe Square is not a magic square n");
return 0;
}
我在这里看到的问题很少
int *arr[SIZE][SIZE] = " "; // this wont compile
declareArray(&arr); // needless
declareArray();
---
int arr[SIZE][SIZE] = {};
declareArray(arr);
//declareArray();
声明函数
int declareArray(int *arr[SIZE][SIZE]) // because function call changed
---
int declareArray(int arr[SIZE][SIZE])
最后在printf和scanf删除不再需要的*运算符
如
scanf("%2d", &*arr[row][col]); // remove *
---
scanf("%2d", &arr[row][col]);
printf("%d", *arr[row][col]); // remove *
---
printf("%d", arr[row][col]);
sum = sum + *arr[row][col]; // remove *
---
sum = sum + arr[row][col];
-
请注意，当您声明数组时，数组的名称是指向数组的第一个元素的指针：
&arr[0] == arr. -
传递给 declareArray 函数的参数是指向整数的指针数组，因此分配了指针所需的空间，但实际整数的空间没有分配，因此当您尝试将整数扫描到
arr[row][col]指向的地址时，您正在尝试写入它所持有的地址， 在您的情况下为 0，地址 0 很可能不在数据段中，因此segment_fault。
那你应该怎么做？
用 malloc() 分配所需的空间，将返回的地址分配给arr[row][col]然后scanf()如下所示，或者更简单更好地使用 int 数组并简单地将整数分配给arr[row][col]如上面的答案所示
#include <stdio.h>
#include <stdlib.h>
#define SIZE 15
int declareArray(int * arr[SIZE][SIZE]);
int main(void)
{
int * arr[SIZE][SIZE] = {0};
declareArray(arr);
return 0;
}
//main logic
int declareArray(int * arr[SIZE][SIZE])
{
//variables
int rowNumber = 0;
int dimension = 0;
int row, col;
int sum, sum1, sum2;
int flag = 0;
int * myVal;
//ask for input of squares
printf("Please enter the dimension of the square: ");
//makes sure the size is between 1 and 15 for the dimension of the square
if(scanf("%d", &dimension) != 1 || dimension >= 15 || dimension < 1)
{
printf("invalid inputn");
return 1;
}
//enter the data
//array rows
for(row = 0; row < dimension; ++row)
{
printf("Please enter the data for row %d: ", ++rowNumber);
//array columns
for(col = 0; col < dimension; ++col)
{
printf("insert data to row %d col %d: ", rowNumber, col+1);
arr[row][col] = (int *) malloc(sizeof(int));
scanf("%2d", arr[row][col] );
}
}
printf("n");
printf("Here is the square");
printf("n");
//print the square
//array rows
for(row = 0; row < dimension; ++row)
{
//array columns
for(col = 0; col < dimension; ++col)
{
printf("%d", *arr[row][col]);
}
printf("n");
}
//Checks Sum of diagonal elements
sum = 0;
for (row = 0; row < dimension; row++) {
for (col = 0; col < dimension; col++) {
if (row == col)
sum = sum + *arr[row][col];
}
}
//Checks Sum of Rows
for (row = 0; row < dimension; row++) {
sum1 = 0;
for (col = 0; col < dimension; col++) {
sum1 = sum1 + *arr[row][col];
}
if (sum == sum1)
flag = 1;
else {
flag = 0;
break;
}
}
//Checks sum of Columns
for (row = 0; row < dimension; row++) {
sum2 = 0;
for (col = 0; col < dimension; col++) {
sum2 = sum2 + *arr[col][row];
}
if (sum == sum2)
flag = 1;
else {
flag = 0;
break;
}
}
//if the sums match, it will print a success message with the constant
//if the sums dont match, a fail message will appear
if (flag == 1)
printf("nTHE SQUARE IS A MAGIC SQUARE WITH A CONSTANT OF %d n", sum);
else
printf("nThe Square is not a magic square n");
return 0;
}