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Java

Posted by SZE SZE XU
SZE SZE XU
9,759 Points

predict output problem related to ++i i++

class output {

 public static void main(String args[])

    {
        char c[]={'a', '1', 'b' ,' ' ,'A' , '0'};

        for (int i = 0; i < 5; ++i)

        {
            if(Character.isDigit(c[i]))

                System.out.println(c[i]+" is a digit");

            if(Character.isWhitespace(c[i]))

                System.out.println(c[i]+" is a Whitespace character");

            if(Character.isUpperCase(c[i]))

                System.out.println(c[i]+" is an Upper case Letter");

            if(Character.isLowerCase(c[i]))

                System.out.println(c[i]+" is a lower case Letter");

            i=i+3;
        }
     }

}

what is the output

a) a is a lower case Letter is White space character

b) b is a lower case Letter is White space character

c) a is a lower case Letter A is a upper case Letter

d) a is a lower case Letter 0 is a digit

the answer is C

but i dont understand i=0+3 , i should be 3 , which is ' ' (white space),

does ++i mean it increments right away which makes i = 1 at that point, if that is the case, why the loop will be executed as i = 0?

thanks.

srikarvedantam
srikarvedantam
8,369 Points

Yes, i = 0 + 3 = 3 happens during the very first iteration, but notice that '++i' (the loop index increment expression, '++i', at the end of the 'for' loop definition) gets executed at the end of the first iteration of the loop.

So, i = 3 + 1 = 4. And, as per the array 'c[]' definition, c[4] = 'A'. And, that explains the Output answer 'C'.

1 Answer

srikarvedantam
srikarvedantam
8,369 Points
srikarvedantam
srikarvedantam
8,369 Points

Yes, i = 0 + 3 = 3 happens during the very first iteration, but notice that '++i' (the loop index increment expression, '++i', at the end of the 'for' loop definition) gets executed at the end of the first iteration of the loop.

So, i = 3 + 1 = 4. And, as per the array 'c[]' definition, c[4] = 'A'. And, that explains the Output answer 'C'.