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Question

Ok so basically I am having trouble finding out why this is not working as I think it should, and need help getting to the right output. I have tried messing with this format a few ways, but nothing works, and I really don't understand why. Here are the instructions, followed by my source for it:

INSTRUCTIONS

Write a loop that reads strings from standard input where the string is either "land", "air", or "water". The loop terminates when "xxxxx" (five x characters) is read in. Other strings are ignored. After the loop, your code should print out 3 lines: the first consisting of the string "land:" followed by the number of "land" strings read in, the second consisting of the string "air:" followed by the number of "air" strings read in, and the third consisting of the string "water:" followed by the number of "water" strings read in. Each of these should be printed on a separate line.

ASSUME the availability of a variable, stdin , that references a Scanner object associated with standard input.

SOURCE:

int land = 0;
int air = 0;
int water = 0;

do
{
     String stdInput = stdin.next();
        if (stdInput.equalsIgnoreCase("land"))
        {
            land++;
        }else if (stdInput.equalsIgnoreCase("air"))
        {
            air++;
        }else if (stdInput.equalsIgnoreCase("water"))
        {
            water++;
        }
}while (stdin.equalsIgnoreCase("xxxxx") == false); // I think the issue is here, I just dont't know why it doesn't work this way
System.out.println("land: " + land);
System.out.println("air: " + air);
System.out.println("water: " + water);

Answer 1

You are storing user info in stdInput but your while checks stdin . Try this way

String stdInput = null;

do {
    stdInput = stdin.next();

    //your ifs....

} while (!stdInput.equalsIgnoreCase("xxxxx"));

Answer 2

This Works:)

I just submitted this code to codelab and it works just fine.

Write a loop that reads strings from standard input where the string is either "land", "air", or "water". The loop terminates when "xxxxx" (five x characters ) is read in. Other strings are ignored. After the loop, your code should print out 3 lines: the first consisting of the string "land:" followed by the number of "land" strings read in, the second consisting of the string "air:" followed by the number of "air" strings read in, and the third consisting of the string "water:" followed by the number of "water" strings read in. Each of these should be printed on a separate line.

int land = 0;
int air = 0;
int water = 0;
String word = "";
while(!(word.equals("xxxxx"))) {
 word = stdin.next();
if(word.equals("land")) {
    land++;
}else if(word.equals("air")) {
    air++;
}else if(word.equals("water")) {
    water++;
} 
}
System.out.println("land:" + land);
System.out.println("air:" + air);
System.out.println("water:" + water);

Answer 3

我认为您想要stdInput.equalsIgnoreCase("xxxxx") == false而不是stdin.equalsIgnoreCase("xxxxx") == false 。

Answer 4

You are right - the problem is where you indicated. The solution is to not read again from stdin:

Also, you must declare the stdInput before the loop so its scope reaches the while condition:

String stdInput = null;
do {
    stdInput = stdin.next();
    // rest of code the same
} while (!stdInput.equalsIgnoreCase("xxxxx"));

An alternate way would be a for loop:

for (String stdInput = stdin.next(); !stdInput.equalsIgnoreCase("xxxxx"); stdInput = stdin.next()) {
    // rest of code the same
}