javafor-loopdefinition

declaring different type variables inside for condition in Java

Is it possible to declare two variables of different types in initialization of for statement in Java?

for (char letter = 'a', int num = 1; maxLine - num > 0; letter++, num++) {
    System.out.print(letter);
}

Coming from C/C#, I tried to do it as above, but the compiler says it expects a semicolon identifier after the letter variable declaration.

Solution

  • Because the variable declaration in a for loop follows that of local variable declaration.

    Similar to how the following is not valid as a local declaration because it contains multiple types:

    char letter = 'a', int num = 1;

    It is also not valid in a for loop. You can, however, define multiple variables of the same type:

    for (int n = 0, m = 5; n*m < 400; n++) {}

    As to why the designers made it that way, ask them if you see them.