Length of array of type String

Question

I have :

string a[] = {"akdhska","asjd","askjdh"};

Is there any way to get the number of elements in this array?

As a resolution of this I am doing the following:

vector<string> a;
a.insert(a.end(),"test1"); // or a.push_back("test1")
a.insert(a.end(),"test");
a.insert(a.end(),"test12");
a.insert(a.end(),"test123");
int len = a.size();

You can use `sizeof(a)/sizeof(*a)` as long you're in the same scope `a` was defined. — πάντα ῥεῖ, Sep 20 '15 at 09:40
If you have a somewhat modern compiler, you can also do `std::vector a = {"akdhska","asjd","askjdh"};` — Bo Persson, Sep 20 '15 at 09:45
how does sizeof work for the String type? By default do we have a fixed siz for each string? — Bhumi Singhal, Sep 20 '15 at 10:45
It isn't the string type that matters here, it is the length of the array. — juanchopanza, Sep 20 '15 at 11:16
@juanchopanza right!! so we are dividing the total length of the array with the length of each block. so we have each block assigned a fixed size. — Bhumi Singhal, Sep 20 '15 at 11:29

score 6 · Answer 1 · answered Sep 20 '15 at 09:41

6

A C++11 solution would be

std::size_t length = std::end(a) - std::begin(a);

or

std::size_t length = std::distance(std::begin(a), std::end(a));

answered Sep 20 '15 at 09:41

lisyarus

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score 1 · Answer 2 · answered Sep 20 '15 at 09:40

1

You can probably use :

int length = sizeof(a)/sizeof(*a);

answered Sep 20 '15 at 09:40

ig-melnyk

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best for compile-time known tables, 0 CPU use (at place when is born) BUT NOT when table is passed as argument – Jacek Cz Sep 20 '15 at 09:44
@JacekCz It depends how it is passed. I.e. what the type of the parameter of the function is. – juanchopanza Sep 20 '15 at 09:45

Andreas DM · Answer 3 · 2015-09-20T09:46:35.087

1

string a[] = {"akdhska", "asjd", "askjdh"};
int len = sizeof(a) / sizeof(*a); // gives you number of elements

edited Sep 20 '15 at 09:46

answered Sep 20 '15 at 09:40

Andreas DM

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best for compile-time known tables, 0 CPU use (at place when is born) BUT NOT when table is passed as argument – Jacek Cz Sep 20 '15 at 09:44

Length of array of type String

3 Answers3