Problems initializing arrays in structs in arrays in structs - c++

Question

I've been tasked to remove some compiler warning. I've been able to boil the problem down to the following example, which I am scratching my head why it won't work. I guess I don't know how to initialize stuff in C++. Any help would be appreciated.
I use g++ like so:
g++ init_arr.cpp
Here's the code. I want to initialize all the people at all the tables in Aisle pizza:
// init_arr.cpp
#include <iostream>
#include <string>
#include <sstream>
using namespace std;
struct Person {
int id;
string name;
double money;
};
struct Table {
Person tab[4];
};
struct Aisle {
Table ais[3];
};
int main() {
cout << "main function()" << endl;
Aisle pizza =
{
{ // Table 0
{ 0, "Tom", 100.0 },
{ 1, "Mary", 101.0 },
{ 2, "Jane", 103.0 },
{ 3, "Joe", 104.0 }
},
{ // Table 1
{ 0, "Tom", 100.0 },
{ 1, "Mary", 101.0 },
{ 2, "Jane", 103.0 },
{ 3, "Joe", 104.0 }
},
{ // Table 2
{ 0, "Tom", 100.0 },
{ 1, "Mary", 101.0 },
{ 2, "Jane", 103.0 },
{ 3, "Joe", 104.0 }
}
};
return 0;
}
I thought the above would work, but I get the following error:
g++ init_arr.cpp -std=gnu++0x
init_arr.cpp: In function ‘int main()’:
init_arr.cpp:49: error: too many initializers for ‘Table [3]’
init_arr.cpp:49: error: too many initializers for ‘Aisle’

Answer 1

While #us2012 showed what works and provides a good explanation (+1 for him), I find it not very readable. This is an alternative:
Aisle pizza =
{
Table { // Table 0
Person { 0, "Tom", 100.0 },
Person { 1, "Mary", 101.0 },
Person { 2, "Jane", 103.0 },
Person { 3, "Joe", 104.0 }
},
Table { // Table 1
Person { 0, "Tom", 100.0 },
Person { 1, "Mary", 101.0 },
Person { 2, "Jane", 103.0 },
Person { 3, "Joe", 104.0 }
},
Table { // Table 2
Person { 0, "Tom", 100.0 },
Person { 1, "Mary", 101.0 },
Person { 2, "Jane", 103.0 },
Person { 3, "Joe", 104.0 }
}
};

Answer 2

You're missing lots of pairs of parentheses. I have added comments to make it clearer which bit starts where.
To put it into one sentence, your problem is that an array with three elements can be initialized with {1,2,3} while a struct that contains an array as its single member is an extra layer and therefore has to be initalized with { {1,2,3} } - the outer layer is the struct, the inner layer is the array.
Aisle pizza =
{ // Aisle init
{ // Table ais[3] init
{ // ais[0] init
{ // Person tab[4] init
{ 0, "Tom", 100.0 },
{ 1, "Mary", 101.0 },
{ 2, "Jane", 103.0 },
{ 3, "Joe", 104.0 }
}
},
{ // ais[1] init
{ // Person tab[4] init
{ 0, "Tom", 100.0 },
{ 1, "Mary", 101.0 },
{ 2, "Jane", 103.0 },
{ 3, "Joe", 104.0 }
}
},
{ // ais[2] init
{ // Person tab[4] init
{ 0, "Tom", 100.0 },
{ 1, "Mary", 101.0 },
{ 2, "Jane", 103.0 },
{ 3, "Joe", 104.0 }
}
}
}
};

Answer 3

Each block needs to represent an object. Aisle struct contains an array object (ais). Each element of the ais array contains a Table struct. Each Table struct contains an array object (tab). and so on...
Try this:
Aisle pizza =
{ // Aisle
{ // .ais
{ // .ais[0]
{ // .ais[0].tab
{ 0, "Tom", 100.0 }, // tab[0]
{ 1, "Mary", 101.0 }, // tab[1]
{ 2, "Jane", 103.0 }, // tab[2]
{ 3, "Joe", 104.0 } // tab[3]
}
},
{ // .ais[1]
{ // .ais[1].tab
{ 0, "Tom", 100.0 }, // tab[0]
{ 1, "Mary", 101.0 }, // tab[1]
{ 2, "Jane", 103.0 }, // tab[2]
{ 3, "Joe", 104.0 } // tab[3]
}
},
{ // .ais[2]
{ // .ais[2].tab
{ 0, "Tom", 100.0 }, // tab[0]
{ 1, "Mary", 101.0 }, // tab[1]
{ 2, "Jane", 103.0 }, // tab[2]
{ 3, "Joe", 104.0 } // tab[3]
}
}
}
};