Correct way of looping through C++ arrays

Question

Recently I have found a lot of examples, most of them regards the C++ 98, anyways I have created my simple-array and a loop (codepad):

#include <iostream> using namespace std;  int main () {    string texts[] = {"Apple", "Banana", "Orange"};    for( unsigned int a = 0; a < sizeof(texts); a = a + 1 )    {        cout << "value of a: " << texts[a] << endl;    }     return 0; } 

Output:

value of a: Apple value of a: Banana value of a: Orange  Segmentation fault

It's working fine, except the segmentation fault at the end.

My question is, does this array/loop through is done a good way? I am using C++ 11 so would like to be sure it fits the standards and couldnt be done a better way?

Answer 1

In C/C++ sizeof. always gives the number of bytes in the entire object, and arrays are treated as one object. Note: sizeof a pointer--to the first element of an array or to a single object--gives the size of the pointer, not the object(s) pointed to. Either way, sizeof does not give the number of elements in the array (its length). To get the length, you need to divide by the size of each element. eg.,

for( unsigned int a = 0; a < sizeof(texts)/sizeof(texts[0]); a = a + 1 ) 

As for doing it the C++11 way, the best way to do it is probably

for(const string &text : texts)     cout << "value of text: " << text << endl; 

This lets the compiler figure out how many iterations you need.

as others have pointed out, std::array is preferred in C++11 over raw arrays; however, none of the other answers addressed why sizeof is failing the way it is, so I still think this is the better answer.