Assignment
8
Write a program in C++ to swap two numbers using reference
variable.
Program
Code with explanation
1.
#include
<iostream>
2.
using
namespace std;
3.
void
swap(int * a, int * b)
4.
{
5.
int
temp;
6.
temp
= * a ;
7.
*
a = * b ;
8.
*
b = temp;
9.
cout<<“Number
After swap \n”;
10.
cout<<“a
= “<< * a << ” \t b = “<< * b << endl;
11.
}
12.
int
main()
13.
{
14.
int
a, b;
15.
cout<<”
Enter two number to swap using call by value \n”;
16.
cout<<”
Enter first number “;
17.
cin>>a;
18.
cout<<”
Enter second number “;
19.
cin>>b;
20.
cout<<“Number
Before swap \n “;
21.
cout<<“a
= ” << a << “\t b = “<< b << endl;
22.
swap(&a,
&b);
23.
cout<<“Display
values after swap function call completed \n “;
24.
cout<<“a
= ” << a << “\t b = “<< b << endl;
25.
return 0;
26.
}
Explanation
of Code:
Line No. 1 and 2: include the Library file
and stander input – output functions.
Line
No. 3 to 11:
User defined function of call by reference. Swap function has two
arguments. Call statement of swap function at Line No 22. The function call statement contains the address of actual parameter. At
function called statement, they are copied to the pointer of the formal
parameter.
In swap function
scope, we can swap the values using third variables. Actually, swap the variable
by pointing to the variable of the main function. So swap variable in user
defined function reflected in main function.
Line No. 12: main function header.
Line No. 13 and 24: Begin and end of main
function respectively.
Line No. 14: Create two integer variables.
Line No. 15 to 19: Accept two integer
variables using appropriate massage.
Line
No. 20 to 21:
Display the values of variables before swap.
Line
No. 22:
call swap function using two parameters. These two parameters are actual
parameter. Address of actual parameter copy into pointer of formal parameter at
line no 3. Change the values of
formal parameter are reflected actual parameter.
Line No. 23 and 24: Actual parameters are swap. Displayed variables to check it.
Line
No. 25:
return statement appropriate with main function return data type.
Program
Code for run:
#include
<iostream>
using
namespace std;
void
swap(int * a, int * b)
{
int
temp;
temp
= * a ;
*
a = * b ;
*
b = temp;
cout<<“Number
After swap \n”;
cout<<“a
= “<< * a << ” \t b = “<< * b << endl;
}
int
main()
{
int
a, b;
cout<<“Enter
two number to swap using call by value\n”;
cout<<“Enter
first number “;
cin>>a;
cout<<“Enter
second number “;
cin>>b;
cout<<“Number
Before swap \n”;
cout<<”
a = ” << a << “\t b = ” << b <<endl;
swap(&a,
&b);
cout<<“Display
values after swap function call completed \n “;
cout<<“a
= ” << a << “\t b = “<< b << endl;
return
0;
}
Output
of Program:
Enter
two number to swap using call by value
Enter
first number 10
Enter
second number 20
Number
Before swap
a = 10
b = 20
Number
After swap
a
= 20 b = 10
Display
values after swap function call completed
a = 20
b = 10
