How to fix template problem in C++

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I was programming a simple program in c++ but i get an error saying No matching function for call to 'passarray'

here is my code:

C++

#include <iostream>
#include <string.h>
#include <vector>

using namespace std;

template <typename t, typename t2>

void passarray(vector<t> myvec, T2 value) {
    myvec.push_back(value);
}

template <typename... t, typename t2>
void givevalue(vector<t2> myvec,T... myval) {
    passarray(myvec, myval...);
}

int main(){
    vector<int> myvec;
    givevalue(myvec, 233, 45);
}

Can someone please tell me why the code is not running and how to fix it. Thank you

What I have tried:

I have tried looking up the problem and trying to learn more on variadic template.

Posted 2-Sep-21 1:08am

iwanttoaskquestions

Updated 2-Sep-21 2:46am

Richard MacCutchan

v6

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Richard MacCutchan 2-Sep-21 8:07am

I am not an expert in templates, but it would appear that you are trying to pass a parameter pack(multiple items) to a function that only accepts a single value.

You also need to check your typenames are all the correct spelling and case(i.e. T2 is not the same as t2).

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CPallini · Accepted Answer · 2021-09-02T02:46:00

Solution 1

Try

C++

#include <iostream>
#include <vector>

using namespace std;

template <typename T>
  void passarray(vector<T> &  myvec, T value)
  {
    myvec.push_back(value);
  }

template <typename T>
  void givevalue(vector <T> & v){}

template <typename T, typename... Ts>
  void givevalue(vector<T> & v, T x, Ts... xs)
  {
    passarray(v, x);
    givevalue(v, xs...);
  }


int main()
{

  vector<int> myvec {12,7};

  givevalue(myvec, 5, 6, 7);
  givevalue(myvec, 42);

  for (auto x : myvec)
    cout << x << " ";

  cout << endl;
}

Posted 2-Sep-21 2:46am

CPallini

Updated 2-Sep-21 2:47am

v2

Comments

iwanttoaskquestions 3-Sep-21 1:39am

Thank you it works. But I am having a problem understanding why. Can you please explain it to me?

CPallini 3-Sep-21 2:41am

Try to remove

template <typename T>
  void givevalue(vector <T> & v){}

and see the error messages, to have some insight.
Moreover, I suggest you to read some tutorials on variadic templates, the could explain better than me what is happening.