C编程，这是一个无限循环吗？

Question

What would happen if the follow lines were a part of a compiled program?

void main() {
    int x = 5;
    while (x == 5); 
}//end main

I believe it is, I have compiled it, and the screen just stays the same, I also tried to add after the while statement

int y = 10;
printf("%i", y);

and then end main. However it never prints. So I am fairly certain that its an infinite loop but I would just like to be sure.

Answer 1

是的，这是一个无限循环，因为永远不会满足退出循环的条件：因为变量 x 在循环内永远不会改变，循环的条件将始终为真。

Answer 2

Yes, it's an infinite loop. Remember, while the condition is true the while loop will continue. As 5 will always be equal to 5 the condition will always be true, even if you don't do anything inside the while loop.

Answer 3

Yes it is, but it could actually leave the loop in some scenarios:

• There is a thread that changes the x variable.
• An external program modifies the program memory.
• As tadman said, a bitflip occurs on the memory itself, which is very unlikely but also a possibility.

There must be other cases where the loop can end, but those are the ones I could think of.

If you're interested, you can try to do so with Cheat Engine to change the value of x.

Answer 4

try:

void main() {
    int x = 5;
    while (x == 5){
        printf("%d\n", x);
    } 
}

Use format %d for doubles