CODEWITHSUNDEEP
c++vectorreference
Svetsi
Svetsi

Reputation: 305

Pass a vector by reference C++

I can't figure out why this won't work? I need to pass the vector reference so I can manipulate it from an external function.

There are several questions on this on the internet but I can't understand the replies?

code below:.

#include <iostream>
#include <vector>
#include <string>


using namespace std;

string funct(vector<string> *vec)
{
    cout << vec[1] << endl;

}



int main()
{

vector<string> v;
v.push_back("one");
v.push_back("two");
v.push_back("three");


}

Upvotes: 0

Views: 10871

Answers (1)

Shashank Shet
Shashank Shet

Reputation: 334

Firstly you need to learn the differences between references and pointers and then the difference between pass-by-reference and pass-by-pointer.

A function prototype of the form:

void example(int *);  //This is pass-by-pointer

expects a function call of the type:

int a;         //The variable a
example(&a);   //Passing the address of the variable

Whereas, a prototype of the form:

void example(int &);  //This is pass-by-reference

expects a function call of the type:

int a;       //The variable a
example(a);

Using the same logic, if you wish to pass the vector by reference, use the following:

void funct(vector<string> &vec)  //Function declaration and definition
{
//do something
}

int main()
{
vector<string> v;
funct(v);            //Function call
}

EDIT: A link to a basic explanation regarding pointers and references:

https://www.dgp.toronto.edu/~patrick/csc418/wi2004/notes/PointersVsRef.pdf

Upvotes: 9

Related Questions