Assignment
7
Write a program in C++ to swap two numbers using call by
value.
Program
Code with explanation
1.
#include
<iostream>
2.
using
namespace std;
3.
void
swap(int a, int b)
4.
{
5.
int
c;
6.
c
= a ;
7.
a
= b ;
8.
b
= c;
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 value.
Swap function has two arguments. Call statement of swap function at Line No 22. The function call statement contains the actual parameter, they are copied to the formal parameter of the called function.
Values
of actual parameter are copy in formal parameter. Formal Parameters can be used as local variables. In
the swap function, formal parameters create local variables. These local
variables will be swap using third variable. This means that there will be no
change in the actual parameter.
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. Values of actual parameter copy into formal parameter at line no 3.
Change the values of formal parameter are not affected the actual parameter.
We swap formal parameters but no
change in actual parameter. After function call completed.
Line
No. 23 and 24: There was no change in
the actual parameters. 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 = 10
b = 20
