Will there any performance impact of a Class definition structure order in C ?-CodePudding

I have two classes as follows (C ):

class A {
private:
    int v1;
    char c;
    long long v2;
    double v3;
    bool f1();
    bool f2(int x);
    void f3(int y);
    struct Node tempNode;
public:
    A();
};


class B {
private:
    int v1;
    char c;
    long long v2;
    double v3;
    struct Node tempNode;
    bool f1();
    bool f2(int x);
    void f3(int y);
    
public:
    B();
};

Class B just has struct Node tempNode declaration moved from after functions declarations in A to all members declarations first then methods in class B.

My doubt is, will class B more efficient than class A simply due to this reordering? or they will perform at the same level. Let me know even if the gains in B is very small.

CodePudding user response：

No, both classes will be laid out exactly the same in memory. Thus there's no performance difference.

Note that (non-virtual) member functions do not affect the layout of the data in memory. If you disregard them, you can easily see that both classes have the same layout.

CodePudding user response：

will class B more efficient than class A simply due to this reordering?

No. Order of member functions in relation to data members or to each other has no effect on the program.