The Islamic University of Gaza
Engineering Faculty
Department of Computer Engineering
Fall 2017
ECOM 2003
Muath i.Alnabris
Computer Programming: C++
Experiment #4
Loops Part II
Experiment #3:Loops Part II
Contents
 Loop Control Statement
 Nested loop
 Loop Control Statement
Loop control statements change execution from its normal sequence. When
execution leaves a scope, all automatic objects that were created in that scope are
destroyed.
C++ supports the following control statements.
Sr.No
1
2
3
2
Control Statement & Description
break statement
Terminates the loop or switch statement and transfers execution
to the statement immediately following the loop or switch.
continue statement
Causes the loop to skip the remainder of its body and immediately
retest its condition prior to reiterating.
goto statement
Transfers control to the labeled statement. Though it is not
advised to use goto statement in your program.
Experiment #3:Loops Part II
 break Statement
The break; statement terminates a loop (for, while and do..while loop) and a
switch statement immediately when it appears.
 Syntax
break;
In real practice, break statement is almost always used inside the body of
conditional statement (if...else) inside the loop.
 How break statement works?
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Experiment #3:Loops Part II
EX1: C++ program to add all number entered by user until user enters 0.
In the above program, the test expression is always true.
The user is asked to enter a number which is stored in the variable number. If the user
enters any number other than 0, the number is added to sum and stored to it.
Again, the user is asked to enter another number. When user enters 0, the test expression
inside if statement is false and body of else is executed which terminates the loop.
Finally, the sum is displayed.
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Experiment #3:Loops Part II
 continue Statement
It is sometimes necessary to skip a certain test condition within a loop. In
such case, continue; statement is used in C++ programming.
 Syntax
continue;
In practice, continue; statement is almost always used inside a conditional
statement.
 How continue statement works?
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Experiment #3:Loops Part II
EX2: Write program to display integer from 1 to 10 except 6 and 9..
In above program, when i is 6 or 9, execution of statement cout << i << "\t"; is skipped
inside the loop using continue; statement.
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Experiment #3:Loops Part II
 goto Statement
goto statement is used for altering the normal sequence of program
execution by transferring control to some other part of the program.
 Syntax
goto label;
... .. ...
... .. ...
... .. ...
label:
statement;
... .. ...
in the syntax above, label is an identifier. When goto label; is encountered, the
control of program jumps to label: and executes the code below it.
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Experiment #3:Loops Part II
 How continue statement works?
EX3: Write program calculates the average of numbers entered by user If
user enters negative number, it ignores the number and calculates the
average of number entered before it...
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Experiment #3:Loops Part II
You can write any C++ program without the use of goto statement and is generally
considered a good idea not to use them (: .
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Experiment #3:Loops Part II
 Nested Loop
A loop can be nested inside of another loop. C++ allows at least 256 levels of
nesting.
 Syntax
The syntax for a nested for loop statement in C++ is as follows
for ( init; condition; increment ) {
for ( init; condition; increment ) {
statement(s);
}
statement(s); // you can put more statements .
The syntax for a nested while loop statement in C++ is as follows
while(condition) {
while(condition) {
statement(s);
}
statement(s); // you can put more statements.
}
The syntax for a nested do...while loop statement in C++ is as follows
do {
statement(s); // you can put more statements.
do {
statement(s);
} while( condition );
} while( condition );
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Experiment #3:Loops Part II
EX4: Write program uses a nested for loop to find the prime
numbers from 2 to 100
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Experiment #3:Loops Part II
Lab Work:
1- Write program to Check Armstrong Number or not ;
Note: A positive integer is called an Armstrong number if the sum of cubes of
individual digit is equal to that number itself. For example:
153 = 1 * 1 * 1 + 5 * 5 * 5 + 3 * 3 * 3
Armstrong number.
12 is not equal to 1 * 1 * 1 + 2 * 2 * 2
Armstrong number.
// 153 is an
// 12 is not an
2- Write program to print half pyramid using *
Note: User will entered the number of row
*
* *
* * *
* * * *
* * * * *
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Experiment #3:Loops Part II
 Homework
1- Write program to print pyramid using loop
Note: user will entered the number of row
2- Write program to display prime numbers between two intervals
Output
Enter two numbers(intervals): 20 50 Prime numbers between
20 and 50 are: 23 29 31 37 41 43 47
Good Luck
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