C++ Programming - Functions - Discussion

Function Prototype: A function prototype declares a function's name, return type, and parameter list. It informs the compiler about the function's existence and its signature.

Default Argument: A default argument is a value that is automatically assigned to a parameter if no argument is provided during the function call.  
In the given prototype:

int Function(int Tmp = Show()):
This declares a function named Function that returns an integer.

It takes an optional integer parameter Tmp. If no argument is provided for Tmp, the default value is obtained by calling the Show() function.

Why the other prototypes are invalid:
float Function(int Tmp = Show(int, float)):
The default argument Show(int, float) is incorrect. A default argument must be a constant expression or a function call that doesn't require any arguments.
float = Show(int, float) Function(Tmp);:

This is not a valid function prototype. It's syntactically incorrect and doesn't follow the standard function declaration format.

Parameters should not be initialized in the function argument.

float = Show(int, float) Function(Tmp);

First know the logic's to execute.

First we should know the logic's to execute a program.

B is incorrect as how do we send the arguments of function show.

The statement in A only matches with the syntax of a function declaration.

In the case of function prototype I think the type of the arguments are to be specified not the variable name, here return type should be specified.

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[B]. float Function(int Tmp = Show(int, float));

In above option there is type but no arguments in show().

Actually the function definition is like this:

returntype funname(type arg1,type arg2) {
body
}
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[D]. float = Show(int, float) Function(Tmp);

in the above function also same error id there.

Yes option A is correct answer because in A function prototyping show function is called but in option B in prototyping of one function another prototyping is given which is not according to the syntax of function prototyping because return typing is not given.