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CSC 28
F
UNDAMENTALS
OF
COMPUTERPROBLEMSOLVING
Topic 4:Repetition Control Structure (Part 3)
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Objectives
o Nested loop
o Infinite loop
o breakand continuestatement
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o A loop (inner loop) as one of the statements in the body of
anotherloop (outer loop)
o Syntax :-
while (co nd it ion 1) for ( )
{ {
while (cond it ion 2) for ( )
{ {
} }
} }
Nested Loop
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condition1
Statement block2
false
true
condition2
Statement block1
false
true
Nested Loop
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Nested Loop Pseudocode
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o Example 1 :- to print a rectangle
for (outer=0; outer< 7; outer++)
{ for (inner = 0; inner < 4; inner++)
cout
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o Example 2 :- to print a multiplication table of series of 1 to
5int row = 1;
while (row
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Infinite Loop
A loop is called infinite when the loop repeats itselfrepeatedly
with no end.
int x = 0;
while (x == 0)
{
cout
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How to Stop a Loop
Known number of iterations beforethe loop stops (for)
Test for a user-controlled
conditionbefore or after eachiteration (while,do-while)
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o Break Statemento Causes an exit from
enclosing loop or switch
statement.
o In a nested loop, it will onlystop the loop that it is in.
o Continue statemento Skipsthe remaining statementsin the loop
and proceed with
the next loop.
o It is used in a loop structure toalter the flow of control or
to
check for the incorrect data.
o May only be used in while, forand do-while loops.while
(condition)
{
statement-1;
if (condition)break;
statement-2;
}
statement -3
while (condition)
{
statement-1;if (condition)
continue;
statement-2;
}
statement -3
breakand continuestatement
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break Example
int x;
for (x = 1; x
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continueExample
int x;
for (x = 1; x
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Common Loop Errors
This will lead to an infinite loop!int count = 1;
while(count
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Common Loop Errors
Balance may not become equal zero due to
numericalinaccuracies!while(balance != 0.0)
{
balance = balance - amount;
}
Be sure to initialize to 0 a variable used for sums! Be sure to
initialize to 1 a variable used for products!while(power
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END
Thank You
