0
Still curious? Ask our experts.
Chat with our AI personalities
Ezra
Lao
SteveAdd your answer:
Earn +20 pts
How can you explain reverse polish notation in simple words?
Reverse Polish Notation (RPN) is a system where expressions are evaluated from left to right, with no precedence, with operators stated following the operands. A typical RPN expression might be ab+c*, which in infix means (a+b)*c. (Infix is our "standard" system which we use when writing programs) Note that the infix expression required parenthesis to override operator precedence, but the RPN expression did not. If you said in infix a+b*c, the RPN equivalent would be abc*+. The value of RPN is that it is easy to build a stack machine that processes the expression. Each time you encounter an operand, you push it on the stack. Each time you encounter an operator, you process it, replacing the top two elements of the stack with the result (for binary operators), or replacing the top element of the stack with the result (for unary operators). RPN is often used in compiler design.
What is the difference between function prototyping and function overloading?
Function prototypes determine the return type, the name of the function, the argument types expected by the function, and the arity of the function. Function prototyping is used to separate interface from implementation. In C++ all functions must be declared before they are called, thus we use prototypes to provide forward declarations for those functions that have yet to be defined/implemented. We can also use forward declarations for incomplete types such as template functions and classes, however the definition/implementation must be visible to compiler before the function or class is used. In these cases the definitions are typically placed in the same header as the declarations. It is important to note that a definition is also a declaration, and therefore both are also prototypes. The only real difference is that prototypes do not require names for the formal arguments. Even if you provide argument names in your prototypes, they will be ignored by the compiler. The argument names within the definition are the only names of any relevance. Function overloading is where two or more functions share the same name within the same namespace, but have different signatures. The signature of a function is essentially the same as its prototype but excludes the return type, thus overloads cannot differ by return type alone. The compiler uses the function signature to differentiate between your overloads. All function signatures within a namespace must be unambiguous, thus you cannot have two functions with the same name and arguments that are co-variant. For example, the following overloads are invalid because a size_t type is co-variant with unsigned int type, thus the compiler cannot differentiate them. unsigned int max(unsigned int, unsigned int); size_t max(size_t, size_t);
What is a function prototype in C and C plus plus?
A function prototype is basically a definition for a function. It is structured in the same way that a normal function is structured, except instead of containing code, the prototype ends in a semicolon.Normally, the C compiler will make a single pass over each file you compile. If it encounters a call to a function that it has not yet been defined, the compiler has no idea what to do and throws an error. This can be solved in one of two ways.The first is to restructure your program so that all functions appear only before they are called in another function.The second solution is to write a function prototype at the beginning of the file. This will ensure that the C compiler reads and processes the function definition before there's a chance that the function will be called.For example, let's take a look at a few functions form a linked list implementation.// Sample structuresstruct linked_list_node {int data;struct linked_list_node *next;};struct linked_list {int size;struct linked_list_node *root;};// Function Prototypesvoid deleteLinkedList(struct linked_list *list);void deleteNodes(struct linked_list_node *node);// Actual functions:// deletes the given linked listvoid deleteLinkedList(struct linked_list *list) {if( list != NULL ) {// delete nodesdeleteNodes(list->root);// lose the pointerlist->root = NULL;// delete actual listfree(list);}}// deletes all nodes starting at nodevoid deleteNodes(struct linked_list_node *node) {if( node != NULL ) {// deallocate next, if it existsif( node->next != NULL ) {deleteNodes(node->next);// lose the pointernode->next = NULL;}// deallocate nodefree(node);}}
