从C中的int函数返回一个值 [英] Returning a value from an int function in C

问题描述

我在C中有一个int函数，我想出了一个问题。



要启动这里是我的工作！代码：

I have an int function in C and I came up with a question.

To start up here's is my working! code:

int count_numbers(FILE *input) {

	int count = 0;
	fscanf(input, "%d",&count);
	if(count < 1 || count > 30)
	exit(2);
	else
	return count;
}

如果可能的话，我想让代码更干净：

and I wanted to make the code cleaner if possible trying this:

int count_children(FILE *input) {

	int count = 0;
	fscanf(input, "%d",&count);
	count < MIN || count > MAX ? exit(2) : count
}

..那不行！我知道我可以使用上面的语句返回2个值（在开始时使用 return 关键字，但如果我想要这样的话怎么办？int <$ c $会发生什么c> count 当我在第二个函数中使用我的false语句时我无法将值返回给main函数？

...and that won't work! I know that I can return 2 values with the above statement (using return keyword at the start but what if I want to something like that? What happens to int count when i use my false-statement in the second function and I can't return the value to main function?

推荐答案

不，它不会有两个原因：

1）退出函数不返回一个值（它是一个 void 函数： http://www.cplusplus.com/reference/cstdlib/exit/ [ ^ ]）和？：运算符需要两侧的相同类型的值：

2）该函数没有 return 声明！



即使你可以，这也是一个坏主意。仅仅因为你 可以 做某事并不意味着你应该做。我 可以 在高速公路/州际公路上行驶错误 - 但这将是一件愚蠢的事情！



那段代码 - 即使它确实有用 - 也不是更清晰 - 更难阅读和理解。

试试这样：

No, it won't work for two reasons:
1) The exit function does not return a value (it's a voidfunction: http://www.cplusplus.com/reference/cstdlib/exit/[^]) and the ?: operator requires a value of the same type on both sides of the ":"
2) The function does not have a return statement!

Even if you could, it's a bad idea. Just because you can do something doesn't mean you should. I could drive the wrong way up the motorway / interstate - but it would be a stupid thing to do!

That code - even if it did work - isn't tidier of clearer - it's harder to read and understand.
Try like this:

int count_numbers(FILE *input) {

    int count = 0;
    fscanf(input, "%d",&count);
    if(count < 1 || count > 30) exit(2);
    return count;
}

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