Difference between foo(void) and foo()

Source: http://stackoverflow.com/

Consider these two function definitions
void foo(){ ... }
void foo(void){ ..... }
What is the difference between these two functions?

Hint: The answer depends whether this is C code or C++ code.


  1. The difference is this,
    foo(void) is the same in C/C++ a function with no arguments.
    foo() in c++ also means the same as above.
    foo() in c means that we there is not specified about the arguments of function foo() and about the type.

  2. Taken from the book :The Complete Reference C++ - Page 626 - Edition #4

    int f();
    In C this means that the function f may or Might not have any parameters !!
    In C++ "Super Set Of C"
    int f() is same as int f(void)
    because void parameter list is optional in C++
    But programmers put void inside () making it clear that no parameters are accepted by function !!

    Example ::

    C Code :
    void f()
    puts("hello there");
    int main()

    The above code will compile without error and print "hello there"

    C++ example:

    using namespace std;
    void f( )
    cout<<"from f"<<endl;
    int main()
    return 0;

    The above code will say that(compiler)
    too many arguments supplied !!


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