First Prototype gone bad...

Hey guys, so ive jsut started teaching my self C++ and so far ive been doing ok. Today i worked on coding my own original prototype based of the example used. Code Blocker kicked back a lot of errors and i cant figure out why or what i am doing wrong. please help if you guys can.

thanks guys. glad to be a part of the community. and hopefully this code is nice and clean enough for you guys. let me know if i should post differently next time.
Josh

Code:

---

#include <iostream>

using namespace std;
int age ( int x, int y );

int main()
{
    int x;
    int y;
    cout<<"Please input the month you were born (number form): ";
    cin>> int x;
    cin.ignore();
    cout<<"Please input the year of your birth: ";
    cin>> int y;
    cin.ignore();
    cout<<"your age is:"<< age ( x, 2011 - y ) <<"\n";
    cin.get();

}
int age ( int x, int y );
{
    return x, 2011 - y
}

---

Sometimes clearer compiler messages really help.

Quote:

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Comeau C/C++ 4.3.10.1 (Oct 6 2008 11:28:09) for ONLINE_EVALUATION_BETA2
Copyright 1988-2008 Comeau Computing. All rights reserved.
MODE:strict errors C++ C++0x_extensions

"ComeauTest.c", line 11: error: type name is not allowed
cin>> int x;
^

"ComeauTest.c", line 11: error: expected a ";" (perhaps on the previous statement)
cin>> int x;
^

"ComeauTest.c", line 14: error: type name is not allowed
cin>> int y;
^

"ComeauTest.c", line 14: error: expected a ";" (perhaps on the previous statement)
cin>> int y;
^

"ComeauTest.c", line 16: warning: variable "y" is used before its value is set
cout<<"your age is:"<< age ( x, 2011 - y ) <<"\n";
^

"ComeauTest.c", line 16: warning: variable "x" is used before its value is set
cout<<"your age is:"<< age ( x, 2011 - y ) <<"\n";
^

"ComeauTest.c", line 21: error: expected a declaration
Wild guess: Should this be in a function block?
{
^

5 errors detected in the compilation of "ComeauTest.c".

---

In general, it seems you're really confused about how to call a function. When you do call a function, you pass in values for the function to use, which it calls x and y.

Since the function does 2011 - y, you should not need to do it when you call. Also, what is x really for? It's not doing much. The comma operator is just a sequence point (like semicolon), it doesn't have any mathmatical significance.

I'd say your confusion goes beyond not knowing how to call a function.

Take a closer look at your examples, start small, and work your way up slowly. I'm talking adding 3-4 lines at a time, and compiling and making sure it works the way you expect before moving on.

Delete all the code you've written. See if you can read in a variable and print it back out, and work your way up from there.

I struggled with that (and apparently still do after revisiting!) but your problems seem to be:

Code:

---

cout<<"your age is:"<< age ( x, 2011 - y ) <<"\n";

---

This should be written as

Code:

---

cout<<"your age is:"<< age ( x, y ) <<"\n";

---

You're trying to define it twice, use the blueprints/prototype until you define it at the end.
-----

Code:

---

int age ( int x, int y );
{
    return x, 2011 - y
}

---

The int age (int x, int y ) should not have a ';' after it in this part (not the first time it comes up).
-----

Code:

---

{
    return x, 2011 - y
}

---

There should be a ';' after the return part. Also, I don't know if it's necessary, but brackets certainly look nicer:

Code:

---

{
    return (x, 2011 - y);
}

---

-----
For the sake of tidiness, you can enter the different variables on one line:

Code:

---

    cout<<"Please input the month you were born (number form): ";
    cin>> int x;
    cin.ignore();
    cout<<"Please input the year of your birth: ";
    cin>> int y;

---

Should be:

Code:

---

    cout<<"Please input your DOB (mm yyyy): ";
    cin>> int x >> int y;

---

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I think that addresses everything, but I had a play around and came up with this (I'm sure it can be improved on, but it runs without those dreaded errors!)

Code:

---

#include <iostream>

using namespace std;
int age ( int x, int y, int z );

int main()
{
    int x;
    int y;
    int z;
    cout<<"Please input your date of birth (dd mm yyyy): ";
    cin>> x >> y >> z;
    cin.ignore();
    cout<<"your age is:"<< age ( x, y, z ) <<"\n";
    cin.get();
}
int age ( int x, int y, int z )
{
    return ((30-x)/360)+((6 - y)/12) + (2011 - z);
}

---

I suppose I'd have to link it up to a database to get the exact date right with the varying days of the months, or use a function, or create one of my own (but with my skills at the moment, we're talking hours there...). Also, I don't know the variable to give a decimal instead of an integer, so it won't be as precise as I'd have liked. Hope this helps!

Maybe someone can help me with my do...while loop question now? http://cboard.cprogramming.com/cplus...tch-cases.html

Quote:

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Originally Posted by rwebb2305

Also, I don't know if it's necessary, but brackets certainly look nicer:

---

I prefer to leave out the parentheses, but there's a bigger problem than just style: the comma used here is the comma operator. x is evaluated, then 2011 - y is evaluated, and then the result of 2011 - y is returned. If the aim is to compute the age in months, then obviously the correct computation must be substituted.

Quote:

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Originally Posted by rwebb2305

For the sake of tidiness, you can enter the different variables on one line:

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Yes, but that's the wrong syntax. x and y must be declared first, then one can write:

Code:

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cin >> x >> y;

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That said, x and y are poorly chosen names here. month and year would be more descriptive.

@rwebb2305
Don't forget when doing integer math any fractional part is dropped. So in your function ((30-x)/360) will evaluate to zero. As will (6 - y)/12). Which would leave (2011 - z) as the only part of the equation that produces an output.

Jim