c - c中for循环的一个例子

Question

我遇到了以下问题:

下面的for循环会运行多少次-

for(;0;)
 printf("hello");

我执行了它运行了 1 次。我无法理解怎么办？

Answer 1

即使执行 1 次也不会执行。我猜你的编译器不好？

好的。我认为您正在使用 Turbo C ;-)

编辑:

来自 C99 标准:

6.8.5.3 The for statement 1 The statement

for ( clause-1 ; expression-2 ; expression-3 )

statement behaves as follows: The expression expression-2 is the controlling expression that is evaluated before each execution of the loop body. The expression expression-3 is evaluated as a void expression after each execution of the loop body. If clause-1 is a declaration, the scope of any variables it declares is the remainder of the declaration and the entire loop, including the other two expressions; it is reached in the order of execution before the first evaluation of the controlling expression. If clause-1 is an expression, it is evaluated as a void expression before the first evaluation of the controlling expression.134)

它明确指出在执行循环之前首先评估条件。任何符合标准的编译器都不应该执行循环 for(;0;) {}，哪怕是一次。