Std 12 Computer Chapter 7 Java Basics (Part 3) by Nuzhat Memon Block in java Control structures in java Branches in java if statement switch statement loops in java for loop while loop do while loop break statement and continue statement gseb computer paper solution 2020 english medium

1. Chapter 7
Java Basics
Part 3 Control Structures
Presented by nuzhat memon
- Branches (if statement & switch statement)
- Loops (for, while, do while)
- Break and Continue Statement

2. Presented by Nuzhat Memon
Block statement
+ A block statement is a group of statements enclosed between a pair of braces, { and }
+ Block can be used for various purpose as follows:
 To group a sequence of statements into a unit that is to be treated as a single statement.
 To group logically related statements.
 To create variables with local scope for statements within a block.
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SwapNo:
{ // start of block
int a=10, b=20;
System.out.println(“Value of a is “+a);
System.out.println(“Value of b is “+b);
int temp=a;
a=b;
b=temp;
System.out.println(“Now value of a is “+a);
System.out.println(“Now value of b is “+b);
} // end of block

3. Presented by Nuzhat Memon 3
branches/decision/selective
Control Structures
loops
Do while loop
For loop While loop
If statement Switch case
In general, the statements are executed sequentially, one by one. Sometimes,
program logic needs to change the flow of this sequence.
The statements that enable to control the flow of execution are considered as
control structures
Control Structures

4. Presented by Nuzhat Memon
Branches (or Decision or selective structure)
Branches are used to choose among two or more possible courses of action,
also called decision or selective structure
(1) IF STATEMENT
 Used in a program to take one of two alternative coursed of action,
depending upon Boolean valued expression.
 When if statement is executed, it first evaluates boolean expression
 If its value is true, it executes statement1;
 Otherwise it executes statement2 written after keyword else
(2) SWITCH STATEMENT
 Used when there are many alternative actions to be taken depending
upon the value of a variable or expression.
 Test expression should be of the type byte, char, short or int or enum
 This test expression is compared with each of the case values.
 If a match is found, the following statement is executed.
 If no match is found, the default statement is executed.
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if(boolean expression){
statement1;
}
Else{
statement2;
}
Switch (expression){
case 1:
statement1;
break;
case 2:
statement2;
break;
default:
statementN;
}

5. Presented by Nuzhat Memon 5
Entry controlled or pre-test
loop constructs.
It is used when numbers of
iterations are pre-defined.
Entry controlled or pre-test
loop constructs.
It is used when number of
iterations are not
pre-determined.
Exit controlled or post-test
loop constructs.
Here, statements of loop are
executed at least once.
Do while loop
Looping
For loop While loop
for (initialize; condition; iteration){
statements;
}
//initialize
while (condition){
statements;
increment/decrement statement;
}
//initialize
Do{
statements;
incr/decr statement;
} while (condition);
 Loops are used to repeat a sequence of statements over and over until some
condition occurs. Loop are executed if condition is true.
 Java supports 3 types of looping constructs:
Looping (Repetitive Control Structures)

6. Presented by Nuzhat Memon
Questions:
 Which of the following is compiled error free?
(A)for(;;){int i=7}; (B) while (1) { int i=7};
(C) while (true){int i=7} (D) All of these
 What will be output of following program?
class abc{
public static void main(string[] S){
for(int i=0;i<10;i++){
SYSTEM.out.println(i);
}
}
}
(A) error (B) i (C) Display 1 to 10 (D) 1,2,3,…….10
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7. Presented by Nuzhat Memon
Statement
BREAK STATEMENT
+ Used to transfer the control outside switch/loop
structure.
+ It is used to exit the loop.
+ It is jumps outside the nearest loop containing
this statement.
CONTINUE STATEMENT
+ It is used to skip the following statement in a loop
and continue with the next iteration.
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for(){
if(condition){
break;
}
statementss;
}
for(){
if(condition){
continue;
}
statements;
}

8. Presented by Nuzhat Memon
Thanks!
Any questions?
You can find me at:
+ nuzhatmemon.com
+ nuzhat.memon@gmail.com
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