Question

What is the difference between the way original C and C89 deal with an actual parameter whose type is not identical to that of the corresponding formal parameter?

Answer 1

The original C language did not provide any checks or restrictions on mismatched parameter types, leading to undefined behavior. The C89 standard introduced prototype declaration, allowing type checking for actual parameter types.

Step-by-step explanation:

In the original C programming language, if the type of the actual parameter is not identical to the type of the corresponding formal parameter, the compiler would not issue an error, but the behavior of the program would be undefined. This means that the program could produce unexpected results or crash, as there is no guarantee on how the mismatched types would be handled.

However, in the C89 standard, a new feature called 'prototype declaration' was introduced. This allowed the programmer to specify the types of the function parameters, and if the actual parameter types did not match the specified types, the compiler would issue an error. This provided better type checking and improved program reliability.