对于循环的前和后语句为空

Question

In Golang what does it means that the pre and post statements of a for loop are empty like in this example:

    sum := 1
    for ; sum < 10; {
        sum += sum
    }
    fmt.Println(sum)

Answer 1

Remember that a for loop is the same as a while loop. Your code can be rewritten in other languages as

sum := 1
while(sum < 10) {
    sum += sum
}
fmt.Println(sum)

In a for loop, there are 3 parts.

for(initial statement ; condition ; end statement usually iterate)

This is equivalent to

initial statement
while(condition) {
    Stuff here
    End iteration statement
}

The reason your loop can be written withiut the pre and post statements is because you've specified them in other parts of the code.