Java syntax
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Iteration statements are statements that are repeatedly executed when a given condition is evaluated as true. Since J2SE 5.0, Java has four forms of such statements. The condition must have type boolean or Boolean, meaning C's
while (1) {
doSomething();
}
results in a compilation error.
while loop
In the while loop, the test is done before each iteration.
while (i < 10) {
doSomething();
}
do ... while loop
In the do ... while loop, the test is done after each iteration. Consequently, the code is always executed at least once.
// doSomething() is called at least once
do {
doSomething();
} while (i < 10);
for loop
for loops in Java include an initializer, a condition and a counter expression. It is possible to include several expressions of the same kind using comma as delimiter (except in the condition). However, unlike C, the comma is just a delimiter and not an operator.
for (int i = 0; i < 10; i++) {
doSomething();
}
// A more complex loop using two variables
for (int i = 0, j = 9; i < 10; i++, j -= 3) {
doSomething();
}
Like C, all three expressions are optional. The following loop is infinite:
for (;;) {
doSomething();
}
Enhanced for loop