C语言 如何在C中对函数进行排序？“函数的先前隐式声明在这里”错误
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How to sort functions in C? "previous implicit declaration of a function was here" error
提问by Randalfien
I'm sure this has been asked before, but I couldn't find anything that would help me. I have a program with functions in C that looks like this
我确定以前有人问过这个问题，但我找不到任何可以帮助我的东西。我有一个带有 C 函数的程序，看起来像这样
function2(){
function1()
}
function1 (){
function2()
}
main () {
function1()
}
It's more complicated than that, but I'm using recursion. And I cannot arrange the function in the file so that every function would only call functions that are specified above itself. I keep getting an error
它比那更复杂，但我正在使用递归。而且我无法在文件中安排函数，以便每个函数只能调用上面指定的函数。我不断收到错误
main.c:193: error: conflicting types for 'function2'
main.c:127: error: previous implicit declaration of 'function2' was here
How do I avoid this? Thanks in advance for suggestions and answers.
我如何避免这种情况？预先感谢您的建议和答案。
回答by pmg
You need to declare (not define) at least one function before using it.
在使用它之前，您需要声明（而不是定义）至少一个函数。
function2(); /* declaration */
function1() { function2(); } /* definition */
function2() { function1(); } /* definition */
int main(void) { function1(); return 0; }
回答by Andrew White
Foward declare your functions...
转发声明你的功能......
function1();
function2();
function2(){
function1()
}
function1 (){
function2()
}
main () {
function1()
}
回答by Andrew White
Try:
尝试：
function1();
function2();
function2(){
function1()
}
function1 (){
function2()
}
main () {
function1()
}
回答by Jens Gustedt
Forward declare your functions, but by using prototypes. If you have a lot of them such that you can't handle this, this is the moment to think of your design and to create a .h file with all your prototypes. Use
Forward 声明您的函数，但使用原型。如果你有很多这样你无法处理这个问题，现在是考虑你的设计并创建一个包含所有原型的 .h 文件的时候了。用
int function1(void);
int function2(void);
if that was what you meant. int function1()already is different from that in C. Help the compiler such that he can help you.
如果那是你的意思。int function1()已经与 C 中的不同。帮助编译器，以便他可以帮助您。
回答by Anshu Sharma
This is how C works. We need to declare the function before use. like when you use any variable, you must have declare first then you would have use it.
这就是 C 的工作方式。我们需要在使用前声明函数。就像使用任何变量时一样，您必须先声明，然后才能使用它。
Declaration:- function1(); function2(); and then put your own code.
声明：- function1(); 函数2(); 然后放上自己的代码。
