function call in c 2b 2b

1#include <iostream>
2using namespace std;
3//REMOVE COMMENTS TO USE VARIOUS FUNCTION CALLING METHODS
4// function declaration
5void swaper(int &,int&) ;// call  by reference
6//void swaper(int *,int * );// call by address
7//void swaper(int,int );//call by value
8
9
10int main () {
11   // local variable declaration:
12   int a = 100;
13   int b = 200;
14   /* calling a function to swap the values using variable reference.*/
15   swaper(a, b);// call by reference
16   //swaper(&a, &b); //call by address
17   //swaper(a, b); // call by value
18   cout << "After swap, value of a :" << a << endl;
19   cout << "After swap, value of b :" << b << endl;
20
21   return 0;
22}
23
24//CALL BY refernce DEFINATION
25void swaper(int &x, int &y) // x and y are ref variable..ie they are other name for a and b
26{
27   int temp;
28   temp = x; //save the value as x which is ref for a
29   x = y;    // put y into x
30   y = temp; // put x into y
31}
32//CALL BY ADD DEFINATION
33/*void swaper(int *x, int *y) {
34   int temp;
35   temp = *x; //save the value at address x
36   *x = *y;    // put y into x
37   *y = temp; // put x into y
38*/
39
40// CALL BY VALUE DEFINATION
41/* void swaper(int x, int y) {
42   int temp;
43   temp = x; // save the value of local x
44   x = y;    // put local y into local x
45   y = temp; //put local x into local y
46*/
47
48
49

1// function example
2#include <iostream>
3using namespace std;
4
5int addition (int a, int b)
6{
7  int r;
8  r=a+b;
9  return r;
10}

1void Hello() {
2  std::cout << "Hello";
3}
4
5int main () {
6  Hello();
7}

1#include <iostream>
2#include <stdlib.h>
3#include <iomanip>
4#include <fstream>
5using namespace std;
6
7void function_one(double, double, double);
8
9int main() {
10  double r1 = 1.0;
11  double r2 = 2.0;
12  double x = 0.0;
13  function_one(r1, r2, x);
14  return 0;
15}
16
17void function_one(double rmin, double rmax, double x0) {
18  cout << "Function got called" << endl;
19}