for loop problem

[gurpeet singh]

please refer the kb6 book page no 349. the book says

The next example demonstrates a for loop with multiple variables in play. A
comma separates the variables, and they must be of the same type. Remember that
the variables declared in the for statement are all local to the for loop, and can't
be used outside the scope of the loop

int r;  
float t;
 for( r=6,t=7.0f;r+t<90;r++,t++){}       // here "r" is of type int and t is of type float

why is this happening ?

[John Jai]

I don't have the book for reference. May be the book refers to declaring more than one type in the for loop.

public class ForPlay {
	public static void main(String...args){
		for (int i = 0, j = 0; i < 2; i++){ // valid - both of same type
			System.out.println(i + " " + j);
		}
		
		int i = 0;
		float j = 0;
		for (i = 0, j = 0; i < 2; i++){ // Valid - declaration not in for
			System.out.println(i + " " + j);
		}
		
		for (int k = 0, float f = 0.f, k < 2; k++){// Invalid - two types in declaration
			System.out.println(k + " " + f);
		}		
	}
}

[Helen Ma]

In a for loop , only one type of variable can be declared, according to the KB book.