[Error] C:\Users\刘恪666\Desktop\Mydoc\计网\2.cpp:11: implicit declaration of function `int InitStack(...)'

This error message suggests that the function `InitStack` has not been declared before it is used in the code.

To fix this error, you need to declare the `InitStack` function before using it in your code. You can do this by adding a function prototype at the beginning of your code, like this:

int InitStack(Stack &S);

Make sure to replace `Stack` with the actual name of your stack data type. This function prototype tells the compiler that there is a function named `InitStack` that takes a `Stack` parameter and returns an `int` value.

Alternatively, you can define the `InitStack` function before calling it in your code. This means moving the entire function definition above the code that uses it.