Structure objects allow saving data of different types.

Once the structure is defined, an instance of it must be created in order to access its elements.

void OnStart() {
  struct Structure {
    double arr[];
    int x;
  };
 
  Structure a;  // structure
  ArrayResize(a.arr, ArraySize(a.arr) + 1);
  a.arr[0] = 2;
  a.x = 1;
  Print(" arr[0] = ", a.arr[0], "; x = ", a.x);
 
  Structure b[];  // array
  ArrayResize(b, ArraySize(b) + 1);
  b[0] = a;  // copy the structure because each b[n] is empty
  ArrayResize(b, ArraySize(b) + 1);
  b[1] = a;
  b[1].arr[0] = 4;
  b[1].x = 2;
  Print(" b[0].arr[0] = ", b[0].arr[0], "; b[0].x = ", b[0].x, 
        " b[1].arr[0] = ", b[1].arr[0], "; b[1].x = ", b[1].x);
}

Structures can be used as structure of arrays (SoA) or as array of structures (AoS):

• SoA tends to offer better performances;
• AoS tends to offer better readability of the code.

struct Colour {
    double c[];
};
Colour colour;  // structure of array (SoA)
 
 
struct Shape {
    double s;
};
Shape shape[];  // array of structure (AoS)
 
 
void OnStart() {
  soa();
  aos();
}
 
 
void soa() {  // better performances
  ArrayResize(colour.c, ArraySize(colour.c) + 1);
  colour.c[ArraySize(colour.c) - 1] = 10;
  ArrayPrint(colour.c);
}
 
 
void aos() {  // better clearness
  ArrayResize(shape, ArraySize(shape) + 1);
  shape[ArraySize(shape) - 1].s = 20;
  ArrayPrint(shape);
}