Objective-c 主程序，什么是:int argc, const char * argv[] [英] Objective-c main routine, what is: int argc, const char * argv[]

问题描述

传递给命令行程序的 main 方法的参数是什么:

What are the arguments passed into the main method of a command-line program:

int main(int argc, const char * argv[])

第一个 int 是什么意思?

what is the first int mean?

第二个参数是什么，是一个字符数组?

And what is the 2nd parameter, is that an array of chars?

如何使用这些?

另外，命令行项目类型的实际用途是什么，除了用来学习 obj-c 即练习.

Also, what practical use is a command-line project type, other than using it to learn obj-c i.e. to practise.

推荐答案

argc 表示参数计数".它表示有多少参数被传递到可执行文件中.argv 表示参数值".它是一个指向字符数组的指针.或者换个角度考虑，它是一个C字符串数组(因为C字符串只是字符数组).

argc means "argument count". It signifies how many arguments are being passed into the executable. argv means "argument values". It is a pointer to an array of characters. Or to think about it in another way, it is an array of C strings (since C strings are just arrays of characters).

所以如果你有一个程序foo"并像这样执行它:

So if you have a program "foo" and execute it like this:

foo -bar baz -theAnswer 42

然后在您的 main() 函数中，argc 将是 5，而 argv 将是:

Then in your main() function, argc will be 5, and argv will be:

argv[0] = "/full/path/to/foo";
argv[1] = "-bar";
argv[2] = "baz";
argv[3] = "-theAnswer";
argv[4] = "42";

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