It is possible to assign a structure as a whole:
structure_A = structure_B ;
The above code copies all fields from structure_B
into structure_A
.
It is not possible to compare two structures with the ==
operator.
// DOES NOT COMPARE STRUCTURES
if (structure_A == structure_B)...
To test if two structures are identical, each field must be tested individually.
The scope of the structures is similar to the variables:
It is possible to know the size of a structure in memory with the sizeof()
function.
Be careful, the size of a structure is not always equal to the sum of the size of its fields.
Without going into details, memory alignment allows to increase the execution speed.
Create a vector
structure that contains 3 double precision fields x
, y
and z
.
Create a variable v
of type vector
and display the size
vector
;v
;Here is the expected output:
Size of structure vector : 24 bytes Size of variable v : 24 bytes Size of v.x : 8 bytes Size of v.y : 8 bytes Size of v.z : 8 bytes
The following circle
structure is provided:
struct circle {
int cx,cy; // Center
double radius; // Radius
};
Declare a variable C1
for a circle centered in (2,4) and with a radius of 2.5.
Copy the circle into a new variable C2
previously declared.
Check that the copy has been done correctly (C1 equals C2) and that the variables
C1and
C2` have two distinct addresses:
Circle C1 with radius 2.50 and center (2,4) Circle C2 with radius 2.50 and center (2,4) The structures are identical Address of C1 : 0x7fff25306248 Address of C2 : 0x7fff25306238
To copy a variable of type structure in another ...
To check that variables of type structure are identical ...
==
operator does not work on structures, you have to compare the fields individually. However, in this case, a minimum of 16 bytes is required.
Try again...
What is the size of the structure below?
// Structure circle
struct circle {
int cx,cy; // Center
double radius; // Radius
};