Too few arguments in function call

[Zii]

Alright, I am trying to learn functions (please bear with me) and would like to have a function "SayHello" to print "Hey there, [persons name]". However, I am not sure what I am missing here. I added a "cin << name;" before the function is supported to print, but am unable to compile it due to an error under main().
"Too few arguments in function call" right when you hover over the last closing parenthesis. I tried calling the function under main as "SayHello(name); and that wouldn't compile either.

So how would someone write a function, that as soon as it is called, asks for a users name and take the input, and puts in into the cout "Hey there, ___"?

I can't put "cin >> name;" under the main() because it is not a global variable. If I create a global variable, then it won't pull the same variable from the "name" I just added to the SayHello function.

Help? I'm sure I'm doing something backwards here.

 
#include <iostream>
using namespace std;

void SayHello (string name) 
{
	cin >> name;
	cout << "Hey there, " << name << endl;
}

int main()
{
	SayHello ();

}

[rjphares]

#include <iostream>
using namespace std;

void SayHello () 
{
        string name;
	cin >> name;
	cout << "Hey there, " << name << endl;
}

int main()
{
	SayHello ();

}

[Zii]

Oh, so adding SayHello (string name) inside the parentheses is only useful if I want to declare a custom "name" string directly, inside the main() function when calling the SayHello function?
Just want to make sure.

[keskiverto]

[edit]

#include <iostream>
using namespace std;

void getName(string& name) // #A
{
	cin >> name;
}

string getName() // #B
{
	string name;
	cin >> name;
	return name;
}

void SayHello (string name) 
{
	cout << "Hey there, " << name << endl;
}

int main()
{
	string question;
	question = getName(); // call #B
	SayHello( question );

	getName( question ); // call #A
	SayHello( question );
}

[Handy Andy]

Hello Zii,

In answer to your question. Your code would work better as:

#include <iostream>
#include <string>  // <--- Need this header file for the strings.

//using namespace std;  // <--- Best not to use.
// The most recent post that is worth reading. http://www.cplusplus.com/forum/beginner/258335/
using std::cin;
using std::cout;
using std::endl;
using std::string;

//  Prototypes.
void SayHello(string name);

int main()
{
	std::string name;

	std::cout << "\n Enter your name: ";
	std::getline(cin, name);

	SayHello(name);

	return 0;  // <--- Not required, but makes a good break point.
}

void SayHello(string name)
{
	cout << "\n Hey there, " << name << endl;
}

I did rearrange the program to make some points that you may not be aware of.

First off lines 12 and 26 must match. /this means that the return type and parameters must match. For the parameters they must match in type and order. I find that writing the function definition and copying that to paste in for the prototype works the best. Notice the only difference between the prototype and function definition is the (;) at the end of the prototype.

For a prototype only the variables' type is required, but I find including the variables' name helpful.

The function call, line 21, is slightly different only the variables' name is required the type is not.

I added line 18 because you need a prompt to let the user know what needs to be entered. In the end what you say is your choice, but I would suggest ending the prompt with name: "; . The final space helps and the lack of a "\n" or "endl" puts the "cin" on the same line. I just think it looks nicer this way.

Because you are entering a name I used "std::getline" from the "string" header file. This will put whatever you type into the "name" variable whereas the formatted input, cin >> name; will stop at the first white space or new line whichever comes first. So given a name like "First Last" only "First" will be put in "name" and "Last" will be left in the input buffer for the next "cin" to deal with.

I do not know if you are aware of the difference between pass by value and pass by reference, but keskiverto's program is a very good example.

Andy

[Zii]

Thank you Handy Andy, I really appreciate the super explanation! You are awesome.
And thanks for the example keskiverto.