Question

I am working on a program and part of it requires me to create a struct called DETAILS with the fields name, age, and height. I want to populate the record with data using a function argument. I had numerous problems with this code and had lots of help from here but need a little more. I can’t output the populated struct to the screen. If anyone could help me with this last thing I would be so grateful!

Here is my code:

#include <cstdlib>
#include <iostream>
#include <iomanip>

using namespace std;

const int LEN=100;

struct DETAILS
{
 char name[LEN];
 int age;
 double height;
};

 DETAILS fillperson(struct DETAILS David, const char[LEN], int, double);


int main()
{
 struct DETAILS David;

 fillperson(struct DETAILS David, "David Greene", 38, 180.0);

 cout<<David.name<<endl;
 cout<<David.age<<endl;
 cout<<David.height<<endl;

 return 0;
}

DETAILS fillperson(struct DETAILS David, char name[LEN], int age, double height) 
{
 cout<<"Done"<<endl;
 return;
}

Answer 1

DETAILS fillperson(David, "David Greene", 38, 180.0); //deprecated conversion from string constant to char * [-Wwrite-Strings]

This is because string literals (like “David Greene”) are const, and you’re passing it as just a char[LEN]. Try const char[LEN].

DETAILS fillperson(struct DETAILS, char[LEN] name, int age, double height) //expected , or ... before 'name'

The [] goes after the name of the variable: char name[LEN].

Also, where is this David variable coming from? The name of the variable needs to be in the function signature (struct DETAILS David, not just struct DETAILS).

cin>>David.name>>name;

I think what you really want is:

DETAILS fillperson(struct DETAILS David, const char name[LEN], int age, double height)

EDIT:

I think you misunderstood what I was saying. This line is a weird mix of function definition of function call.

DETAILS fillperson(struct DETAILS David, "David Greene", 38, 180.0);

When you call a function, you don’t declare types:

fillperson(David, "David Greene", 38, 180.0);

But you do need them in the actual function definition, so instead of this:

DETAILS fillperson(struct DETAILS, char[LEN] name, int age, double height) 

Do this:

DETAILS fillperson(struct DETAILS David, char name[LEN], int age, double height)

EDIT 2:

Also, I don’t know what you’re trying to do here (or any of the similar lines):

cin>>David.name>>name;

Are you trying to copy the string? (See strncpy) or read input (cin >> David.name)?

Recommendation

If you’re using C++ and C++ input streams, you should really just use string.

EDIT 3

Your current code won’t work for several reasons:

DETAILS fillperson(struct DETAILS David, char name[LEN], int age, double height) 
{
    cout<<"Done"<<endl;
    return;
}

The function signature says the function returns DETAILS (the first part of the line), but you don’t return anything. Either return the input struct:

return David;

Or make the method return void (nothing):

void fillperson(...

My recommendation about using string is that it’s much easier to work with than straight character arrays (char[]):

string name = “David”;
string name2 = name; // Copying is much easier

So for example, your code could look like this:

#include <cstdlib>
#include <iostream>
#include <iomanip>

using namespace std;

struct DETAILS
{
    string name;
    int age;
    double height;
};

// Note that I'm passing a reference for DETAILS (the &). This means
// that we have access to the actual DETAILS instance from outside
// the method, not just a copy.
void fillperson(struct DETAILS&, const string, int, double);

int main()
{
    struct DETAILS David;

    fillperson(David, "David Greene", 38, 180.0);

    cout<<David.name<<endl;
    cout<<David.age<<endl;
    cout<<David.height<<endl;

    return 0;
}

void fillperson(struct DETAILS &person, const string name, int age, double height) 
{
    person.name = name;
    person.age = age;
    person.height = height;
    cout<<"Done"<<endl;
}