Compiler appears conflicting types for XXX summary of the causes of the error

The literal translation is XXXX has a conflict! For example, the mistake found today is a low level!

The reason for this error is that the function is written after the main function without first declaring it! It should be declared first, then defined, and if only defined, the definition must be written above the main function. By looking at the data, we have summarized some common causes of such errors:

1, because the function declaration is not done first, and the function is after main ().

2, the header file is circular reference, in reference to consider clearly the order of inclusion

3. The header file declaration and definition parameters are slightly different, for example:

The header file declares void Hanlder (const char * buf);

write void Hanlder (char * buf) at definition time;

This is going to happen conflicting types for error problem

Compiler appears conflicting types for XXX summary of the causes of the error