Is Java pass by value or pass by reference?

I want to pass this 2-D array by reference (i mean in called function i would modify the value of this array and nothing will be return but if i again print the array in calling function in should print the changed value)?

• [code] void fun(char **a)   {    //some modification ... each character X will be replaced by 'A' //return nothing } main() {    char **a;  // a 3x3 char array  // initiallize all values with  character 'X'    print a   //print 3 rows each containing 3 'X' .    fun(a);  // here i want to pass 2D array by reference something like                        //fun(&a) or anyother method    print a   //print 3 rows each containing 3 'A' . } [/code ]

• Answer:

  You can do this by three approaches. They are as follows:- Passing the array as an argument:- In this approach, you pass the array you want to modify as an argument. However, you need to understand that unlike 1D array, this array is not automatically degenerated into a pointer because a pointer to a pointer is being used here. So, the body of the function will be as follows:- void foo(int array[][3]) { // body of the code } 2.  Passing the pointer to an array as the argument:- In this approach, you can create a pointer to an array which actually helps you create a two dimensional array and this 1D array can be passed to the function as an argument. int *arr[3]; for(int i = 0;i<3;i++) int *arr[i] = new int(3); void foo(int *array[3]) { // code to be written } foo(arr); 3.   Passing a double pointer as an argument:- In this approach create a pointer to a pointer and allocate memory to it. Then pass it as an argument to the required function. This can be done as follows:- int** arr; arr = new int *[3]; for(int i=0;i<3;i++) arr[i] = new int(3); // now you have the required 2D array // enter the values you want in arr[3][3] void foo(int** a) { // write the code for the array } foo(arr); //print the array here The memory allocation is in C++ but that shouldn't be a big problem.