i would like to know why my getName function isn't working-CodePudding

#include <iostream>
#include <optional>

using namespace std;

void myFunction(optional<string> name = nullopt) {
  if (name == nullopt) {
    cout << "I wish I knew your name!" << endl;
  }
  else {
    cout << "Hello " << name.value() << "!" << endl;
  }
}

void getName(string Name){
    cout << "input name: " << endl;
    cin >> Name;
}
int main()
{
      myFunction();
      getName();
      myFunction(Name);

  return 0;
}

what would i do to make the getName function working ive tried a few things like adding a string as such string Name = getName() but it wasnt working either.

CodePudding user response：

You could just create a function with a return value instead..

#include <iostream>
#include <optional>
#include <string>
using namespace std;

void myFunction(optional<string> name = nullopt) {
  if (name == nullopt) {
    cout << "I wish I knew your name!" << endl;
  }
  else {
    cout << "Hello " << name.value() << "!" << endl;
  }
}

string getName(){
    string Name;
    cout << "input name: " << endl;
    cin >> Name;
    return Name;
}
int main()
{
      
      myFunction();
      myFunction(getName());

  return 0;
}

CodePudding user response：

You are not calling getName function with its defined parameter string name. You should provide a string to your function while calling it getName("name");

CodePudding user response：

Obviously, Your code can not be compiled, because there's no definition of Name in function main(). Even if you fix it, it won't work properly. Because the Name in function main() and getName() are not the same one. The Name in function getName() is just a copy of Name in function main(). To fix it, try change the type of Name in getName() to string&.

void getName(string& name) {

  cout << "input name: " << endl;
  cin >> name;
}

int main() {
  
  string name;
  getName(name);
}