#include <iostream>
using namespace std;
int main(){
int arr[4] = {1,2,3,4};
int arr2[4] = {5,6,7,8};
int **arrPtr;
arrPtr[0] = arr;
arrPtr[1] = arr2;
for (int *a : arrPtr ){
for (int i : a){
cout << i << endl;
}
}
}
I know this implementation is not the way to go but to show the intension at the end. Basically I am trying to print the content of arrays listed by another double pointer. Is there any way to make this code work?
#include <iostream>
int main() {
int m[][4] = {
{ 0, 1, 2, 3 },
{ 4, 5, 6, 7 },
{ 8, 9, 0, 1 },
{ 2, 3, 4, 5 },
};
for(auto &line : m) {
for(auto &value : line) {
std::cout << value << ' ';
}
std::cout << std::endl;
}
}
http://coliru.stacked-crooked.com/a/d603241402fcc886
notice that this also work:
#include <iostream>
int main() {
for(auto &line : (int [][4])
{
{ 0, 1, 2, 3 },
{ 4, 5, 6, 7 },
{ 8, 9, 0, 1 },
{ 2, 3, 4, 5 },
}) {
for(auto &value : line) {
std::cout << value << ' ';
}
std::cout << std::endl;
}
}
line and value of that type. Using a reference variable (auto &) is necessary, because without it, line would be just a pointer without array size information, which is required for range-for. check this: stackoverflow.com/questions/20982514/…The new range-for loop does not work on raw pointer types as they don't contain size information. If you know their lengths in compile time, you can cast them as pointers to arrays and use in range-for. Such code may be good to play with but use std::array, std::vector for real uses.
#include <iostream>
#include <memory>
using namespace std;
int main(){
int arr[4] = {1,2,3,4};
int arr2[4] = {5,6,7,8};
unique_ptr<int*[]> arrPtrHolder(new int*[2]);
int **arrPtr = arrPtrHolder.get();
arrPtr[0] = arr;
arrPtr[1] = arr2;
for (int *a : *(int*(*)[2])(arrPtr)){
for (int i : *(int (*)[4])(a)){
cout << i << endl;
}
}
}
*arrPtrdoesn't point anywhere, so assigning to it is illegal.for (int a : arr){cout << a << endl;}will give you1 2 3 4with no pointers in sight