What is the "continue" keyword and how does it work in Java?
continue
is kind of like goto
. Are you familiar with break
? It's easier to think about them in contrast:
break
terminates the loop (jumps to the code below it).continue
terminates the rest of the processing of the code within the loop for the current iteration, but continues the loop.
A continue
statement without a label will re-execute from the condition the innermost while
or do
loop, and from the update expression of the innermost for
loop. It is often used to early-terminate a loop's processing and thereby avoid deeply-nested if
statements. In the following example continue
will get the next line, without processing the following statement in the loop.
while (getNext(line)) {
if (line.isEmpty() || line.isComment())
continue;
// More code here
}
With a label, continue
will re-execute from the loop with the corresponding label, rather than the innermost loop. This can be used to escape deeply-nested loops, or simply for clarity.
Sometimes continue
is also used as a placeholder in order to make an empty loop body more clear.
for (count = 0; foo.moreData(); count++)
continue;
The same statement without a label also exists in C and C++. The equivalent in Perl is next
.
This type of control flow is not recommended, but if you so choose you can also use continue
to simulate a limited form of goto
. In the following example the continue
will re-execute the empty for (;;)
loop.
aLoopName: for (;;) {
// ...
while (someCondition)
// ...
if (otherCondition)
continue aLoopName;
Let's see an example:
int sum = 0;
for(int i = 1; i <= 100 ; i++){
if(i % 2 == 0)
continue;
sum += i;
}
This would get the sum of only odd numbers from 1 to 100.