How does a C # string evaluate an eigenvalue?

Question

Why is this piece of code

string str = 30 + 20 + 10 + "ddd"; Console.WriteLine(str); 

creates 60ddd ,

and this one

 string str = "ddd" + 30 + 20 + 10; Console.WriteLine(str); 

produces ddd302010 ?

It seems to be very simple, but I can’t lower my head. Please show me the direction I can go in order to find a detailed answer.

Thanks!

Answer 1

The + operators in the expression you show have the same priority, because they are the same operator, so they are evaluated from left to right:

 30 + 20 + 10 + "ddd" -- + (int, int) returns (int)50 ------- + (int, int) returns (int)60 ------------ + (object, string) returns (string)"60ddd" 

Then for another case:

 "ddd" + 30 + 20 + 10 ----- + (string, object) returns (string)"ddd30" ---------- + (string, object) returns (string)"ddd3020" --------------- + (string, object) returns (string)"ddd302010" 

Answer 2

This is because the expression evaluates from left to right. In the first example, 30 + 20 + 10 gives you the string int + string (30 + 20 + 10) - int, "ddd" - string. In the second example, "ddd" + 30 is the string "ddd30", which adds "20" and "10" to it. It is all about order (unless you have paranthesis).

Answer 3

The + operator has different overloads:

int + int = int

int + string = string

string + int = string

In the following expression:

 string str = 30 + 20 + 10 + "ddd"; Console.WriteLine(str); 

The first 30 + 20 received the estimates as integers, so the operator output will be an integer of 50 .

Then 50 + 10 will be evaluated, which are both integers again, so an integer that is 60 will be displayed.

Then 60 + "ddd" , which is an integer + string , the operator in this case displays a string, so 60 + "ddd" will output 60ddd .

In the following expression:

 string str = "ddd" + 30 + 20 + 10; Console.WriteLine(str); 

The first "ddd" + 30 received grades in which the string + integer operation is performed, so the output will be ddd30 .

Then ddd30 + 20 will be evaluated, in which the string + integer operation is performed again, so the output will be ddd3020 .

Then ddd3020 + 10 will be evaluated, in which the string + integer operation is performed again, so the output will be ddd302010 .

Answer 4

It is rated from left to right. The first example contains numbers first, so it starts by calculating numbers. He then finds out that it should be evaluated as a string. The second example is the opposite. It starts with a line and continues with a line.

Answer 5

This is because the order of operations is from left to right. But binding is the last operation. To evaluate the value, the first expression must be calculated.