printing an int value right after a String value

Question

I have the following example code:

int pay = 80;
int bonus = 65;
System.out.println(pay + bonus + " " + bonus + pay);

could someone please explain to me why I get the following output:

145 6580

Answer 1

Because, this is operator overloading issue. Here, First + is plus operator and last + is concat operator.

 System.out.println(pay + bonus + " " + bonus + pay);
                        |                     |
                      (plus)                (concat)

Answer 2

Your code is interpreting the expression from left to right.

1. pay + bonus is interpreted as a mathematical function, so it adds the values to make 145. The + here is a plus operator.
2. The moment you concatenate the " " , Java converts the expression into a String. The + here is a concatenate operator.
3. Performing + pay converts pay to a String and concatenates it, because the expression is a String.
4. Also doing + bonus converts bonus to a String and concatenates it, also because of the previous expression.

Answer 3

First it adds the two variables and at last it concatinates as string because the integers are converted into strings

For concatenation, imagine a and b are integers:

"" + a + b

This works because the + operator is overloaded if either operand is a String. It then converts the other operand to a string (if needed) and results in a new concatenated string. You could also invoke Integer.toString(a) + Integer.toString(b) for concatenation

Answer 4

bonus and pay are both ints, and therefore going to be combined into a single int result.

You need to insert an empty string between them.

Answer 5

首先是plus operator ，最后是concat operator

Answer 6

As the others are saying the compiler is first adding the integer values and then printing the result, after " " the total value is changed to String type and after that + operator is functioning as a concat action. To not get that output, you can do this:

System.out.println(String.valueOf(pay) + String.valueOf(bonus) + " " + String.valueOf(bonus) + String.valueOf(pay));

Answer 7

The 1st pay and bonus in the println returns an integer. So it computes pay+bonus and returns it as an integer before printing it out.

However, after the "". The + operation then becomes a concatenation of strings and everything after that is returned as a concatenated string. Hence, ("" + bonus + pay) would be returned as "6580".

Answer 8

在“”之前，将奖金和奖金作为整数，相加的结果是145。在“”之后，将奖金和奖金作为String的结果是“ 6580”

Answer 9

what is surrounded by " " is referred to as a 'literal print' and gets printed exactly. The "+" sign is the concatenator operator and concatenates the string with the value that is stored in the variables. pay and bonus are declared as int, but is automatically converted to a String for the purpose of printing out.

You can print an arithmetic expression within a System.out.print statement. Use parentheses around the arithmetic expression to avoid unexpected problems.

        System.out.println("ex" + 3 + 4);   // becomes answer 34
        System.out.println("ex" + (3 + 4));   // becomes answer 7