if-then
and if-then-else
statements, the switch
statement can have a number of possible execution paths. A switch
works with the byte
, short
, char
, and int
primitive data types. It also works with enumerated types (discussed in Enum Types), the String
class, and a few special classes that wrap certain primitive types: Character
, Byte
, Short
, and Integer
(discussed in Numbers and Strings).SwitchDemo
, declares an int
named month
whose value represents a month. The code displays the name of the month, based on the value of month
, using the switch
statement.August
is printed to standard output.switch
statement is known as a switch block. A statement in the switch
block can be labeled with one or more case
or default
labels. The switch
statement evaluates its expression, then executes all statements that follow the matching case
label.if-then-else
statements:if-then-else
statements or a switch
statement is based on readability and the expression that the statement is testing. An if-then-else
statement can test expressions based on ranges of values or conditions, whereas a switch
statement tests expressions based only on a single integer, enumerated value, or String
object.break
statement. Each break
statement terminates the enclosing switch
statement. Control flow continues with the first statement following the switch
block. The break
statements are necessary because without them, statements in switch
blocks fall through: All statements after the matching case
label are executed in sequence, regardless of the expression of subsequent case
labels, until a break
statement is encountered. The program SwitchDemoFallThrough
shows statements in a switch
block that fall through. The program displays the month corresponding to the integer month
and the months that follow in the year:break
is not required because flow falls out of the switch
statement. Using a break
is recommended so that modifying the code is easier and less error prone. The default
section handles all values that are not explicitly handled by one of the case
sections.SwitchDemo2
, shows how a statement can have multiple case
labels. The code example calculates the number of days in a particular month:String
object in the switch
statement's expression. The following code example, StringSwitchDemo
, displays the number of the month based on the value of the String
named month
:8
.String
in the switch
expression is compared with the expressions associated with each case
label as if the String.equals
method were being used. In order for the StringSwitchDemo
example to accept any month regardless of case, month
is converted to lowercase (with the toLowerCase
method), and all the strings associated with the case
labels are in lowercase.switch
statement is null
. Ensure that the expression in any switch
statement is not null to prevent a NullPointerException
from being thrown.goto
concept in Java. There are a few constructs that allow you to do some of the things you can do with a classic goto
.break
and continue
statements allow you to jump out of a block in a loop or switch statement.break <label>
allow you to jump out of an arbitrary compound statement to any level within a given method (or initializer block).continue <label>
to continue with the next iteration of an outer loop from an inner loop.return
.continue
) jump downwards. This restriction helps to avoid the goto 'spaghetti code' syndrome inherent in old BASIC, FORTRAN and COBOL code2.fillInStackTrace()
method. The downside is that the exception's printStackTrace()
methods won't give you useful information .. should you ever need to call them.goto
entirely was a pragmatically better solution. If you keep it in a language, there is always some clown who will abuse it.do {..} while(true);
loop in the second example is optimised by Java compilers in order not to evaluate the loop condition.goto
, because it makes the code unstructured and unclear to read. However, you can use break
and continue
as civilized form of goto without its problems.continue before
is executed, the code flow will start again from before
.goto
is a form of branch or jump statement. Many languages support the goto
statement, and many do not (see language support).goto
statement is not necessary to write programs; some combination of the three programming constructs of sequence, selection/choice, and repetition/iteration are sufficient for any computation that can be performed by a Turing machine, with the caveat that code duplication and additional variables may need to be introduced.[1]goto
statements. Use of goto was formerly common, but since the advent of structured programming in the 1960s and 1970s its use has declined significantly. The primary criticism is that code that uses goto statements is harder to understand than alternative constructions. Goto remains in use in certain common usage patterns, but alternatives are generally used if available. Debates over its (more limited) uses continue in academia and software industry circles.gotolabel
goto
statement is often combined with the if statement to cause a conditional transfer of control.IFconditionTHENgotolabel
goto
statement. For example, the C programming language does not permit a jump to a label contained within another function,[2] however jumps within a single call chain are possible using the setjmp/longjmp functions.goto
is 'infinitely abusable', but also suggest that it could be used for end-of-function error handlers and for multi-level breaks from loops.[10] These two patterns can be found in numerous subsequent books on C by other authors;[11][12][13][14] a 2007 introductory textbook notes that the error handling pattern is a way to work around the 'lack of built-in exception handling within the C language'.[11] Other programmers, including Linux Kernel designer and coder Linus Torvalds or software engineer and book author Steve McConnell, also object to Dijkstra's point of view, stating that GOTOs can be a useful language feature, improving program speed, size and code clarity, but only when used in a sensible way by a comparably sensible programmer.[15][16] According to computer science professor John Regehr, in 2013, there were about 100,000 instances of goto in the Linux kernel code.[17]break
and return
from the middle of loops are bad practice as they are not needed in the Böhm-Jacopini result, and thus advocated that loops should have a single exit point.[18] For instance, Bertrand Meyer wrote in his 2009 textbook that instructions like break
and continue
'are just the old goto
in sheep's clothing'.[19] A slightly modified form of the Böhm-Jacopini result allows however the avoidance of additional variables in structured programming, as long as multi-level breaks from loops are allowed.[20] Because some languages like C don't allow multi-level breaks via their break
keyword, some textbooks advise the programmer to use goto
in such circumstances.[14] The MISRA C 2004 standard bans goto
, continue
, as well as multiple return
and break
statements.[21] The 2012 edition of the MISRA C standard downgraded the prohibition on goto
from 'required' to 'advisory' status; the 2012 edition has an additional, mandatory rule that prohibits only backward, but not forward jumps with goto
.[22][23]goto
, since the target code, being drawn from the library, would not know where to jump back to.while
, repeat until
or do
, and for
statementsswitch
a.k.a. case
statements, a form of multiway branchinggoto
s and if
s. Multi-way branching replaces the 'computed goto' in which the instruction to jump to is determined dynamically (conditionally).break
and continue
allow one to terminate a loop or continue to the next iteration, without requiring an extra while
or if
statement. In some languages multi-level breaks are also possible. For handling exceptional situations, specialized exception handling constructs were added, such as try
/catch
/finally
in Java.GOTO
jumps to one of several labels in a list, based on the value of an expression. An example is goto (20,30,40) i
. The equivalent construct in C is the switch statement and in newer Fortran a CASE
statement is the recommend syntactical alternative.[44]BASIC has the ON .. GOTO
construct that achieves the same goal.[45]assign
statement only allows a constant (existing) line number to be assigned to the integer variable. However, it was possible to accidentally treat this variable as an integer thereafter, for example increment it, resulting in unspecified behavior at goto
time. The following code demonstrates the behavior of the goto i
when line i is unspecified:[47]void*
using the unary, prefix label value operator&&
. The goto instruction is also extended to allow jumping to an arbitrary void*
expression. This C extension is referred to as a computed goto in documentation of the C compilers that support it; its semantics are a superset of Fortran's assigned goto, because it allows arbitrary pointer expressions as the goto target, while Fortran's assigned goto doesn't allow arbitrary expressions as jump target.[50] As with the standard goto in C, the GNU C extension allows the target of the computed goto to reside only in the current function. Attempting to jump outside the current function results in unspecified behavior.[50]GOTO i*1000
to jump to the line numbered 1000 times the value of a variable i (which might represent a selected menu option, for example).[51]GOTO
s.goto
statement that is not a traditional GOTO statement at all. It takes a function name and transfers control by effectively substituting one function call for another (a tail call): the new function will not return to the GOTO, but instead to the place from which the original function was called.[54]goto
statement, and many do not. In Java, goto
is a reserved word, but is unusable, although the compiled file.class generates GOTOs and LABELs.[59][60] Python does not have support for goto, although there are several joke modules that provide it.[57][58] In PHP there was no native support for goto
until version 5.3 (libraries were available to emulate its functionality).[61]C# has goto. It also makes case and default statements labels, whose scope is the enclosing switch statement; goto case or goto default is often used to replace explicit 'fall-through', which C# disallows.→
for goto.goto
function in Perl as well.The 'goto' module was an April Fool's joke, published on 1st April 2004. Yes, it works, but it's a joke nevertheless. Please don't use it in real code!
The keywords const and goto are reserved, even though they are not currently used. This may allow a Java compiler to produce better error messages if these C++ keywords incorrectly appear in programs.
Unlike C and C++, the Java programming language has no goto statement; identifier statement labels are used with break (§14.15) or continue (§14.16) statements appearing anywhere within the labeled statement.
break
and continue
statements?break
leaves a loop, continue
jumps to the next iteration.break
continue
break
completely exits the loop. continue
skips the statements after the continue statement and keeps looping.continue outer1;
instead of break outer1;
will cause the loop to continue looping from the outer1
label instead of breaking out of the loop. Note how each time continue outer1;
is called, the code continues from the outer loop after incrementing the loop index i by 1.break
statement results in the termination of the statement to which it applies (switch
, for
, do
, or while
).continue
statement is used to end the current loop iteration and return control to the loop statement.continue
skips the current executing loop and MOVES TO the next loop whereas break
MOVES OUT of the loop and executes the next statement after the loop.I learned the difference using the following code. Check out the different outputs.Hope this helps.break
statement breaks out of the loop (the next statement to be executed is the first one after the closing brace), while continue
starts the loop over at the next iteration.break
statement exists the current looping control structure and jumps behind it while the continue
exits too but jumping back to the looping condition.break
leaves the loop.continue
will go back to start loop.continue
is usedbreak
is used