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Flow
Control
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If -- Statement
This is the simplest form of If statement. When we
have only one condition to evaluate, we should usethis
statement.
if (expression)Statement;
int a = 4if
a>4
printGreater than four
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If else -- Statement
When we have two conditions to evaluate, we should
use this form of if statement.
int a = 4
if
a>4
print Less than
four
print Greater than
four
Y
N
if (expression)
{
Statements;
}
else
{
Statements;
}
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Example:
// program displaying if else statement
public class IfElseStat {public static void main(String args[])
{
int a =4;if(a>4)
System.out.println( Greater than four);else
System.out.println( Less than four);}
}
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If else if -- Statement
When we have more than two conditions to evaluate,we should use
this form of if statement.
if (expression1) {
Statements;
}
else if (expression2) {
Statements;
}
else {
Statements;
}
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NY
N
int m
if
m>40
Print Fail
Y
Read m
if m > 60
Print Ist Div Print IInd Div
Exit
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Example:// program displaying if else ifstatement
public class ElseIfStat {public static void main(String args[])
{
int marks = 86;
if(marks > 40)System.out.println( Fail);
else if(marks < 60)System.out.println( IInd Div);
elseSystem.out.println( Ist Div);
}}
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Else If Ladder
When we have multiple conditions to evaluate, weshould use this
form of if statement.
if (expression1)
Statements;
else if (expression2)
Statements;
else if (expression2)
Statements;else
Statements;
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N
N
N
N
Y
Y
Y
Ym < 60
m < 70
m < 80
Grade A Grade O
m < 90
Grade B
Grade C
Grade D
Exit
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Example:// program displaying else if Ladder
public class ElseIfLadder {
public static void main(String args[]) {int marks = 86;if(marks
< 60)
System.out.println(Grade - D);
else if(marks < 70)System.out.println(Grade - C);
else if(marks < 80)
System.out.println( Grade - B);
else if(marks < 90)System.out.println( Grade - A);else
System.out.println( Grade - O);}
}
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Switch Statement
Switch statement is a
multiple branchingdecision construct based
on a number of conditions.
It tests whether anexpression matches one ofthe numbers of
constant
values and the control is
transferred to one of themany possible points.
switch(expression) {
case 1: { statements
..
break;
}case 2: { statements
..
break;
}
default: { statements
..
break;
}
}
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switch(a)
a=1 a=2 a=3 a=4default
One Two Three Four default
EXIT
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Example:
// program displaying switch Statementpublic class SwitchStat
{
public static void main(String args[]) {int num = 3;switch(a)
{
case 1: { System.out.println(ONE);
break;}
case 2: {System.out.println(TWO);break;
}case 3: {System.out.println(THRRE);
break;}
case 4: {System.out.println(FOUR);
break;}default: {System.out.println(INVALID VALUE);
break;}
}
}
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LoopConstructor Looping
Loop constructs are used to executecertain block of code
repeatedly based
on a condition.
There are three types of loops in Java:
` for loop
`while loop` do .. while loop
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For Statement
` Used to repeat an action for predeterminednumber of times
` Fixed iterations -- Lower bound and the upperbound are
fixed.Syntax offor loop
for(initialization; condition; updation) {
Statements;
}
First expression is initialization, which is executed only once
when
the loop starts and is used to initialize loop variables.
Second
expression is condition expression, which is tested before
each
iteration of the loop. Third expression is an update expression
and it
is executed each time after the loop body executed.
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Example:// program displaying for Statement
public class ForStat {public static void main(String args[])
{
int num = 2;for(int i=0;i
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While Statement
` Although the task of while and for loops issame, the for loop
is generally used when thenumber of iterations are known in advance
and
while loop is used where number of iterations
are not known.
First the condition is evaluated; if it is true then the
statement in the body of the loop
are executed. After the execution, again the condition is
checked and if it is found to
be true then again the statements in the body of loop are
executed. This means that
these statements are executed continuously till the condition is
true and when it
becomes false, the loop terminates and the control comes out of
the loop.
Syntax while loop
while(condition) {
Statements;.
}
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Example:
// program displaying for Statementpublic class WhileStat {
public static void main(String args[]) {int num=2, i=1;
while(i
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Do .. While Statement
` Used to implement infinite looping` First, the statements
inside loop body are
executed and then the condition is evaluated. Ifthe condition is
true, then again the loop body is
executed and this process continues until thecondition becomes
false.
Syntax while loop
do { Statements;.
} while(condition) ;
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Example:
// program displaying for Statementpublic class DoWhileStat
{
public static void main(String args[]) {int num=2, i=1;do {
System.out.println(Num = + num);num = num * i;i++;
} while(i
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Break Statement
` The break statement terminates theinner loop and executes the
statements,
written after it.
` It can be used with while, until and forloops.
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Break Statement
while truedo
..
..
if then
break
fi
..
done
commands
