how to pass a structure to a function in C++? - c++

Question

The structure is defined as
struct state{
string node_name;
int node_no;
int node_val;
int occupant;
vector<int>node_con;
};
state s[100][100]
I want to send it to a function along with i and j values , where s[i][j] , (i->rows , j-> columns) . How will the struct be sent with both i and j ?

Answer 1

This way
void f(StructName (*a)[100], int i, int j) {
}
Please read about two dimensional arrays and pointer to arrays. Alternatively in C++ you can pass it by a reference, which will make it not decay to its first element
void f(StructName (&a)[100][100], int i, int j) {
}

Answer 2

in C there is no way (AFAIK)
in C++ you could do this
template <class T, int N, int M>
void f(T (&a)[N][M])
{
//...
}
Alternatively, you could pass the dimensions manually, or hard-code them

Answer 3

In C, you can wrap it up in another structure :-)
I see stuff that doesn't look like C in your code ...
struct state {
string node_name;
int node_no;
int node_val;
int occupant;
vector<int>node_con;
};
struct wrap {
int i;
int j;
struct state (*ps)[];
};
int main(void) {
struct state s[100][100];
struct wrap x;
x.i = 100;
x.j = 100;
x.ps = s;
fx(x);
return 0;
}

Answer 4

You mean passing an array of structures. I think it should be this:
struct state{
string node_name;
int node_no;
int node_val;
int occupant;
vector<int>node_con;
};
state s[100][100];
void doSomething(state theState[][100], int i, int j)
{
cout << theState[i][j].node_name << endl;
}
int main()
{
s[0][1].node_name = "s[0][1]";
doSomething(s, 0, 1);
}