In C++, any operator is a function.

I= 10 This function assigns I to 10 and returns 10, that is, the value of the expression "i= 10" is 10. You can use j=(i= 10) or omit the brackets.

I++ This function adds 1 to the value of I, but returns the value before I was added.

Function i+3 does nothing. It returns the value i+3.

All assignments of addition, subtraction, multiplication and division (for int) will be treated as a function.

In C++, expressions with semicolons are statements, such as I+3; This is a statement, but it has no effect. . A string of expressions can be separated by commas to form a large expression. The system will calculate each expression from left to right in turn, and the final value of the large expression is the value of the last expression. So, for the expression you gave, I first assigned it to 10, then added 1, and i+3 did nothing, so the value of I was 1 2, but "the expression i= 10, i++.

In practical application, i+3 is rarely used as a statement alone, and it is usually placed in a place like j=i+3. There are quite a few comma expressions, such as

while(scanf("%d "，& ampn)，n+2 & lt； 3) {....}

The conditional judgment in while is: enter n first, when n+2