Page 278 - Computer_Science_F5

4. Rewrite the following if statement of performing the same task, C++
by using the switch-case statement.
Then, draw a flowchart of the given
switch-case statement.
FOR ONLINE READING ONLY
If (k==1)
m+=5;
else if (k==2)
m+=10;
else if (k==3)
m+=16;
else if (k==4)
m+=34;
5. Considers the following code
fragment.
int x;
cin >> x;
switch (x + 3) {
case 5:
cout << x << ‘\n’;
break;
case 10:
cout << x - 3 << ‘\n’;
break;
case 20:
cout << x + 3 << ‘\n’;
break;
}
Determine the output of the above
program when the user enters 3, 7, 9,
19 and 22 respectively.
Iteration or looping control
structure
Suppose you are required to type the
text “C++ programming” ten times,
you will type the code cout<< “C++
programming”<<endl; ten times which
is very tedious. Also, consider you
are a teacher and you want to find the
average marks of each student for a class
of 100 students. To avoid repetition
269
Student’s Book Form Five
Computer Science Form 5.indd 269
programming languages uses looping
or iteration control structure. Looping
control manages repeated executions in
a program. The loop contains two parts: Chapter Four: Object oriented programming with C++
the body of the loop and the control
statement. The control statement tests
the condition provided, and it allows
the repeated execution of the statements
within the loop body. There are three
types of looping or iteration used in the
C++ programming language. These are:
While loop, Do while loop and For loop.
While loop
The while loop allows a program to test
the conditions first before performing
the execution. If the condition is true, the
loop is executed according to the loop
body. Otherwise, the loop terminates.
The syntax of the while loop is given as:
while (loop condition)
{
Statement (s);
}
Figure 4.46 shows the execution flowchart
of the while loop.
Loop
condition
True False
Statement (s)
(loop body)
Figure 4.46: A flowchart of a While loop
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