c++ - 了解简写 C++

Question

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Answer 1

clause 1在 for 循环中是可选的。它说循环直到array[counter].getFooTitle()).find(x)不等于 string::npos或 counter >= fooCnt

&&是短路 AND 运算符。如果您忘记了这部分，请返回您的真值表。

counter < fooCnt && (toLower(array[counter].getFooTitle()).find(x)==string::npos)是表达式 2 和 counter++是表达式-3

counter从而递增。

在6.8.5.3 C标准的:

1774 The statement

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

behaves as follows:

1775 The expression >expression-2 is the controlling expression that is evaluated before each execution of the loop body.

1776 The expression expression-3 is evaluated as a void expression after each execution of the loop body.

1777 If clause-1 is a declaration, the scope of any identifiers it declares is the remainder of the declaration and the entire loop, including the other two expressions;

1778 it is reached in the order of execution before the first evaluation of the controlling expression.

1779 If clause-1 is an expression, it is evaluated as a void expression before the first evaluation of the controlling expression.134)

1780 Both clause-1 and expression-3 can be omitted.

1781 An omitted expression-2 is replaced by a nonzero constant.

顺便说一句，for 循环也可以被认为是 while 循环。