什么是'？' 在代码中

Question

谁能解释这些代码？为什么它?在那里？

package course.examples.theanswer;

import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;

public class TheAnswer extends Activity {

public static final int[] answers = { 42, -10, 0, 100, 1000 };
public static final int answer = 42;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    setContentView(R.layout.answer_layout);

    TextView answerView = (TextView) findViewById(R.id.answer_view);


    int val = findAnswer();
    String output = (val == answer) ? "42" : "We may never know";
    answerView.setText("The answer to life, the universe and everything is:\n\n"
                    + output);
}

private int findAnswer() {
    for (int val : answers) {
        if (val == answer)
            return val;
    }
    return -1;
}
}

Answer 1

它的条件/三元运算符.

String output = (val == answer) ? "42" : "We may never know";

实际上与:

if(val==answer)
{
 output = "42" 
}

else
{
output = "we may never know"
}