Easy tutorial for C / C ++ - struct 4 (function call methods)

Easy tutorial for C / C ++ - struct 4 (function call methods)

- We have reviewed the function part by three call methods: call by value, call by reference, and call by address. All three of these methods can be applied to struct. Let's look at an example.

Example Code

#include <iostream>

using namespace std;

struct t_Struct{

   int num;

   char fruit[30];

   char color[30];

};

void C_V(t_Struct);

void C_A(t_Struct *);

void C_R(t_Struct &);

int main() {

     t_Struct V1 = {10, "banana" , "red"};

     t_Struct V2 = {20, "apple"  , "black"};

     t_Struct V3 = {30, "orange" , "white"};

     C_V(V1);

     t_Struct *pt;

     pt = &V2;

     C_A(pt);

     C_R(V3);

     return 0;

}

void C_V(t_Struct A)

{

          cout << " ### Call by value ### " << endl ;

          cout << " number = " << A.num << endl ;

          cout << " fruit  = " << A.fruit << endl ;

          cout << " color  = " << A.color << endl ;

          cout << endl;

}

void C_A(t_Struct *A)

{

          cout << " ### Call by address ### " << endl ;

          cout << " number = " << A->num << endl ;

          cout << " fruit  = " << A->fruit << endl ;

          cout << " color  = " << A->color << endl ;

          cout << endl;

}

void C_R(t_Struct &A)

{

          cout << " ### Call by reference ### " << endl ;

          cout << " number = " << A.num << endl ;

          cout << " fruit  = " << A.fruit << endl ;

          cout << " color  = " << A.color << endl ;

          cout << endl;

}

- We have defined a struct 't_Struct' which has integer variable 'num' and string variables 'fruit' and 'color' as member variables.

(1) We have declared the function 'C_V' by call by value method. We got the struct 't_Struct' as a parameter and output the contents of the member variables of the struct variable that was received as an argument.

(2) We have declared 'C_A' function by call by address method. The struct pointer variable was taken as argument and the contents of the member variable of the struct variable are output.

(3) We have declared 'C_R' function by call by reference method. We took the reference variable as an argument and output the contents of the member variables of the struct variable.

- Struct variables V1, V2, V3 were declared and initialized respectively. We first call function 'C_V' with V1 as its argument.

- The structure pointer variable 'pt' were declared and substituted the starting address value of the struct variable 'V2'. And we called function 'C_A' and gave 'pt' as an argument. Finally, we call the function 'C_R' with the reference variable as an argument.

results :

 ### Call by value ###

 number = 10

 fruit  = banana

 color  = red

 ### Call by address ###

 number = 20

 fruit  = apple

 color  = black

 ### Call by reference ###

 number = 30

 fruit  = orange

 color  = white

- You can see the results by three call methods.