CODEWITHSUNDEEP
c++arrays
blackbear2014
blackbear2014

Reputation: 45

error: 'begin' was not declared in this scope

I am new to C++ and I would like to know how to use the sort function. This is my code and it's not working for some reasons:

#include <fstream>
#include <algorithm>
#include <vector>

using namespace std;

int main()
{
    ifstream in("date.in");
    ofstream out("date.out");
    int v[5]= {2, 3 ,1, 0, 5};
    sort(begin(v), end(v));
    for(int j=0; j<5; j++){
        out<<v[j]<<" ";
    }
    return 0;
}

The error code I get is:

error: 'begin' was not declared in this scope

Upvotes: 1

Views: 15134

Answers (4)

S_Anuj
S_Anuj

Reputation: 373

Add the following line to your code:

#include<algorithm>

Upvotes: -1

Malcolm McLean
Malcolm McLean

Reputation: 6404

There are two solutions.

std::sort takes an iterator to the start of the sequence, and one to one past the end of the sequence. This is the convention for stl algorithms which work on collections.

So

 std::vector v = {2, 3, 0, 1, 5};
 sort(v.begin(), v.end());

or

 int v[5] = {2, 3, 0, 1, 5};
 sort(v, v + 5);

plain pointers are iterators as well as stl::iterator types declared in the stl headers.

Upvotes: 2

Shravan40
Shravan40

Reputation: 9908

You need to include the #include <iterator>. Because std::begin defined under iterator.

Or else change the type from array to vector and your code will work.

Upvotes: 4

Yaman Jain
Yaman Jain

Reputation: 1247

replace sort(begin(v), end(v)); with sort(v, v + 5)); v is an array not a vector. For vectors use sort(v.begin(), v.end());

Upvotes: 0

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