Look at the code below;
public class Dois {
public static void main(String[] args) {
int a = 3;
int b = 4;
System.out.print(" " + 7 + 2 + " ");
}
}
The result is 72, but I thought it was for the result to be 7 + 2 that would give 9.
Why did he print 72? Is he following any rules?
Because + occurs soon after a string , " " , then the object there is of type string . Operators are overloaded (in Java this is half a gambiarra, but still it is), so in each type of data, the operator can execute a different thing. You can not define your own overloads, but the so-called primitive types in Java already have one ready. The + when it finds a string is a concatenation operation, so it joins all the texts and does not make sums.
In this case Java decided that it would be poor typing and auto-coercion for string because the initial expression was string . Then " " + 7 gives " 7" , then " 7" + 2 gives " 72" and finally " 72" + " " gives " 72 " .
So it's this, overloading partial weak typing have made Java give this result that looks weird, but it does make some sense, even though it's a questionable rule.
Just put parentheses around the operation and java will perform the operation instead of the cancatenar.
public class testes {
public static void main(String[] args){
int a = 3;
int b = 4;
System.out.print(" " + (7 + 2) + " ");
}
}