Iterative Method
- Iterative statement
- while()
- do-while()
- for()
- for-each() 1.5v
while()
If we don't know the number of iterations in advance then we should go for a while loop.
Example-:
/*
while(rs.next()){
}
while(e.hasmoreElements()){
}
while(itr.hasNext()){
}
*/
the argument should be the boolean type if we are trying to provide any other type then we will get compile time error.
syntax-:
while(b){
statements;
}
this syntax is applicable to c and C++ but this terminology is not allowed in Java.
while(1){
System.out.print("hello");
}
compile time error-:
incompatible type error
found int type
required boolean.
curly-braces are optional and without curly braces, we can take only one statement under while which should not be a declarative statement.
Example-:
/*
while(true)
statement;
valid
while(true);
valid
while(true)
int x=10;
invalid
while(true){
int x=10;
} valid
*/
/*
while(true){
System.out.pirnt("hello");
}
System.out.print("hi");
compile time error
unreachable statement
System.out.print("hi")
while(false){
System.out.print("hello");
}
System.out.print("hi");
compile time error
unreachable statement
{
int a=10,b=20;
while(a<b){
System.out.print("hello");
}
System.out.print("hi");
output "hello" infinite time
int a=10,b=20;
while(a>b){
System.out.print("Hello");
}
System.out.print("Hi");
output-"Hi"
final int a=10,b=20;
while(a<b){
System.out.print("Hello");
}
System.out.print("Hi");
compile time error
unreachable statement
final int a=10,b=20;
while(a>b){
System.out.print("Hello");
}
System.out.print("Hi");
compile time error
unreachable statement
{
*/
Note-: Every final variable will be replaced by a value at compile time only.
Note -: If every argument is the final variable (compile time constant) then that operation should be performed at compile time only.
do-while()
if we want executed loop body at least once then we should go for do while.
syntax-:
do{
body;
}while(condition);
curly braces are optional and without curly braces, we can take only one statement b/w do and while which should not be a declarative statement.
/*
do{
statement;
}while(true);
valid
do;
while(true);
valid
do
int x=10;
while(true);
NotValid
do{
int x=10;
}while(true);
valid
do
while(true);
NotValid
*/
spacial case
do while(true)
System.out.print("hello");
while(false);
we can write this
do
while(true)
System.out.print("Hello");
while(false);
is valid
