c - 我如何初始化双指针有什么问题？

Question

当我运行我的程序时，它只是挂起。我的双指针设置有什么问题吗？如果我将此注释掉，我的程序不会挂起。

double **transverse;
transverse = malloc(rows*sizeof(double*));  //allocate memory to double pointer
for (i = 0; i < rows; i++)
{
    transverse[i] = malloc(rows*sizeof(double*));
    for (j = 0; j < rows; j++)
        transverse[i][j] = 0;
}

Answer 1

你的第二次分配是错误的

transverse[i] = malloc(rows*sizeof(double*));

它应该是

transverse[i] = (double*)malloc(rows*sizeof(double));

traverse[i]是 a double *，因此，您需要使用sizeof(double).

Answer 2

for (i = 0; i < rows; i++)
{
    //Just double for allocating memory for double pointer transverse[i]
    transverse[i] = malloc(rows*sizeof(double));  //<-- remove double*
    for (j = 0; j < rows; j++)
        transverse[i][j] = 0;
}