Accessing structure's variable in C++?

Question

struct app
{   int id;
    char name[20];
    char developer[20];
    char type[20];
    int date_uploaded [3];
};
.
.
.
void search(app a[2])
{
    int choice;
    char t_check[20];
    Dhome();
    cout<<"\n\nSelect the way you want to search for an app"
        <<"\n(1) To search by app name"
        <<"\n(2) To search by developer name"
        <<"\n(3) To search by type"
        <<"\n(4) To return to previous menu\n";
    cin>>choice;
    cin.ignore();
    switch(choice)
    {
        case 1:
            Dhome();
            cout<<"\n\nEnter the app's name: ";
            search_specific(a,"name");
            //Similar cases for passing developer and type
    }
}
void search_specific(app a[2], char choice[10])
    {   int i, flag=0;
        char t_check[20], s_type[5];
        gets(t_check);
        for(i=0; i<2; i++)
        {
        if(strcmp(t_check, a[i].choice)==0)
            {
                flag=1;
                break;
            }
        }
        if(flag==1)
        {
            cout<<"\nThe app was found and its details are as below"
                <<"\nApp ID: "<<a[i].id
                <<"\nApp Name: "<<a[i].name
                <<"\nDeveloper Name: "<<a[i].developer
                <<"\nType: "<<a[i].type
                <<"\nDate Uploaded: "<<a[i].date_uploaded[0]<<"/"<<a[i].date_uploaded[1]<<"/<<a[i].date_uploaded[2];
            cout<<"\n\nPress enter to return to the previous menu";
            getch();
            return;
        }
        if(flag==0)
        {
            cout<<"\nThe app was not found";
            cout<<"\n\nPress enter to return to the previous menu";
            getch();
            return;
        }

    }

Now the problem is that I can't use a[i].choice because the compiler tries to find 'choice' in the structure app. I want it to refer to its value i.e name, developer or type. How can I accomplish this?

Please read: stackoverflow.com/help/mcve

legends2k
– legends2k

2014-12-16 07:37:30 +00:00
Commented Dec 16, 2014 at 7:37 — legends2k
– legends2k, Commented Dec 16, 2014 at 7:37
app doesn't have a member named choice.

Retired Ninja
– Retired Ninja

2014-12-16 07:37:57 +00:00
Commented Dec 16, 2014 at 7:37 — Retired Ninja
– Retired Ninja, Commented Dec 16, 2014 at 7:37

Codor · Accepted Answer · 2014-12-16 07:38:07Z

1

You would have to formulate a switch statement, reading the desired member of a value of type app like the following.

int choice;
// read choice from somewhere
switch(choice)
{
    case 0:
        // do something with a[i].id
        break;
    case 1:
        // do something with a[i].name
        break;
    default;
        break;
}

The members of a struct cannot be accessed index-wise.

answered Dec 16, 2014 at 7:38

Codor

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1 Comment

Ayush Patel Over a year ago

Thanks, but if I use switch then i will have to reproduce the search_specific code in each case.

Chris Culter · Accepted Answer · 2014-12-16 07:47:00Z

0

The C++ language doesn't offer first-class properties that you can reflect over at run time, like JavaScript does. So there's no one-line answer to your question. Maybe the closest thing to what you're looking for is a std::map. But if you're working with a struct like app, you'll have to write your own code to fetch each field from an object, as in Codor's example.

answered Dec 16, 2014 at 7:47

Chris Culter

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