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C++ Programming Code Examples

C++ > Data Structures Code Examples

Single linked list

/* Single linked list */ #include<iostream.h> #include<conio.h> #include<stdlib.h> class list { struct node { int data; node *link; }*p; public: void inslast(int); void insbeg(int); void insnext(int,int); void delelement(int); void delbeg(); void dellast(); void disp(); int seek(int); list(){p=NULL;} ~list(); }; void list::inslast(int x) { node *q,*t; if(p==NULL) { p=new node; p->data=x; p->link=NULL; } else { q=p; while(q->link!=NULL) q=q->link; t=new node; t->data=x; t->link=NULL; q->link=t; } cout<<" Inserted successfully at the end.. "; disp(); } void list:: insbeg(int x) { node *q; q=p; p=new node; p->data=x; p->link=q; cout<<" Inserted successfully at the begining.. "; disp(); } void list::delelement(int x) { node *q,*r; q=p; if(q->data==x) { p=q->link; delete q; return; } r=q; while(q!=NULL) { if(q->data==x) { r->link=q->link; delete q; return; } r=q; q=q->link; } cout<<" Element u entered "<<x<<" is not found.. "; } void list:: delbeg() { cout<<" The list before deletion: "; disp(); node *q; q=p; if(q==NULL) { cout<<" No data is present.. "; return; } p=q->link; delete q; return; } void list:: dellast() { cout<<" The list before deletion: "; disp(); node *q,*t; q=p; if(q==NULL) { cout<<" There is no data in the list.. "; return; } if(q->link==NULL) { p=q->link; delete q; return; } while(q->link->link!=NULL) q=q->link; q->link=NULL; return; } list::~list() { node *q; if(p==NULL) return; while(p!=NULL) { q=p->link; delete p; p=q; } } void list::disp() { node *q; q=p; if(q==NULL) { cout<<" No data is in the list.. "; return; } cout<<" The items present in the list are : "; while(q!=NULL) { cout<<" "<<q->data; q=q->link; } } void list :: insnext(int value,int position) { node *temp,*temp1; temp=p; if(temp1==NULL) { temp1= new node; temp1->data=value; temp1->link=NULL; p=temp1; return; } for(int i=0;((i<position)&&(temp->link!=NULL)) ;i++) { if(i==(position-1)) { temp1= new node; temp1->data= value; temp1->link=temp->link; temp->link=temp1; } temp=temp->link; } //cout<<" Inserted successfully at the position.."<<position; disp(); } int list::seek(int value) { node *temp; temp=p; int position=0; while(temp!=NULL) { if(temp->data==value) return position+1; else { temp=temp->link; position=position+1; } } cout<<" Element "<<value<<" not found"; return 0; } void main() { list l; int ch,v,p,ps; do { clrscr(); cout<<" Operations on List.. "; cout<<" 1.Insertion 2.Deletion 3.Display 4.Seek 5.Exit"; cout<<" Enter ur choice:"; cin>>ch; switch(ch) { case 1: cout<<" 1.Insertion at begining 2.Insertion at the end "; cout<<"3.Insertion after the mentioned position "; cout<<" Enter ur choice:"; cin>>ps; cout<<" Enter the value to insert:"; cin>>v; switch(ps) { case 1: l.insbeg(v); break; case 2: l.inslast(v); break; case 3: cout<<" Enter the position to insert the value:"; cin>>p; l.insnext(v,p); break; default: cout<<" The choice is invalid "; return; } break; case 2: cout<<" 1.Delete the first element 2.Delete the last element"; cout<<" 3.Enter the element to delete from the list"; cout<<" Enter ur choice:"; cin>>ps; switch(ps) { case 1: l.delbeg(); cout<<" The list after deletion: ";l.disp(); break; case 2: l.dellast(); cout<<" The list after deletion: ";l.disp(); break; case 3: l.disp(); cout<<" Enter the element to delete : "; cin>>v; l.delelement(v); cout<<" The list after deletion: ";l.disp(); break; default: cout<<" The option is invalid... "; break; } break; case 3: l.disp(); break; case 4: l.disp(); cout<<" Enter the element to search:"; cin>>v; cout<<" The position of the element "<< v<<" is "<<l.seek(v); getch(); break; case 5: exit(1); default: cout<<" The option is invalid... "; return; } getch(); }while(ch!=5); getch(); return; }

The cin object is used to accept input from the standard input device i.e. keyboard. It is defined in the iostream header file. C++ cin statement is the instance of the class istream and is used to read input from the standard input device which is usually a keyboard. The extraction operator(>>) is used along with the object cin for reading inputs. The extraction operator extracts the data from the object cin which is entered using the keyboard. The "c" in cin refers to "character" and "in" means "input". Hence cin means "character input". The cin object is used along with the extraction operator >> in order to receive a stream of characters.

Deallocate storage space. Default deallocation functions (single-object form). A delete operator is used to deallocate memory space that is dynamically created using the new operator, calloc and malloc() function, etc., at the run time of a program in C++ language. In other words, a delete operator is used to release array and non-array (pointer) objects from the heap, which the new operator dynamically allocates to put variables on heap memory. We can use either the delete operator or delete [ ] operator in our program to delete the deallocated space. A delete operator has a void return type, and hence, it does not return a value.

#include is a way of including a standard or user-defined file in the program and is mostly written at the beginning of any C/C++ program. This directive is read by the preprocessor and orders it to insert the content of a user-defined or system header file into the following program. These files are mainly imported from an outside source into the current program. The process of importing such files that might be system-defined or user-defined is known as File Inclusion. This type of preprocessor directive tells the compiler to include a file in the source code program.

A program shall contain a global function named main, which is the designated start of the program in hosted environment. main() function is the entry point of any C++ program. It is the point at which execution of program is started. When a C++ program is executed, the execution control goes directly to the main() function. Every C++ program have a main() function.

In C++, classes and structs are blueprints that are used to create the instance of a class. Structs are used for lightweight objects such as Rectangle, color, Point, etc. Unlike class, structs in C++ are value type than reference type. It is useful if you have data that is not intended to be modified after creation of struct. C++ Structure is a collection of different data types. It is similar to the class that holds different types of data. A structure is declared by preceding the struct keyword followed by the identifier(structure name). Inside the curly braces, we can declare the member variables of different types.

Switch statement in C tests the value of a variable and compares it with multiple cases. Once the case match is found, a block of statements associated with that particular case is executed. Each case in a block of a switch has a different name/number which is referred to as an identifier. The value provided by the user is compared with all the cases inside the switch block until the match is found. If a case match is NOT found, then the default statement is executed, and the control goes out of the switch block. • The expression can be integer expression or a character expression. • Value-1, 2, n are case labels which are used to identify each case individually. Remember that case labels should not be same as it may create a problem while executing a program. Suppose we have two cases with the same label as '1'. Then while executing the program, the case that appears first will be executed even though you want the program to execute a second case. This creates problems in the program and

A destructor is a special member function that works just opposite to constructor, unlike constructors that are used for initializing an object, destructors destroy (or delete) the object. Destructors in C++ are members functions in a class that delete an object. They are called when the class object goes out of scope such as when the function ends, the program ends, a delete variable is called etc. Destructors are different from normal member functions as they don't take any argument and don't return anything. Also, destructors have the same name as their class and their name is preceded by a tilde(~).

The main purpose of C++ programming is to add object orientation to the C programming language and classes are the central feature of C++ that supports object-oriented programming and are often called user-defined types. A class is used to specify the form of an object and it combines data representation and methods for manipulating that data into one neat package. The data and functions within a class are called members of the class.

The cout is a predefined object of ostream class. It is connected with the standard output device, which is usually a display screen. The cout is used in conjunction with stream insertion operator (<<) to display the output on a console. On most program environments, the standard output by default is the screen, and the C++ stream object defined to access it is cout. The "c" in cout refers to "character" and "out" means "output". Hence cout means "character output". The cout object is used along with the insertion operator << in order to display a stream of characters.

In computer programming, we use the if statement to run a block code only when a certain condition is met. An if statement can be followed by an optional else statement, which executes when the boolean expression is false. There are three forms of if...else statements in C++: • if statement, • if...else statement, • if...else if...else statement, The if statement evaluates the condition inside the parentheses ( ). If the condition evaluates to true, the code inside the body of if is executed. If the condition evaluates to false, the code inside the body of if is skipped.

The getch() is a predefined non-standard function that is defined in conio.h header file. It is mostly used by the Dev C/C++, MS- DOS's compilers like Turbo C to hold the screen until the user passes a single value to exit from the console screen. It can also be used to read a single byte character or string from the keyboard and then print. It does not hold any parameters. It has no buffer area to store the input character in a program. The getch() function does not accept any parameter from the user. It returns the ASCII value of the key pressed by the user as an input.

The exit function terminates the program normally. Automatic objects are not destroyed, but static objects are. Then, all functions registered with atexit are called in the opposite order of registration. The code is returned to the operating system. An exit code of 0 or EXIT_SUCCESS means successful completion. If code is EXIT_FAILURE, an indication of program failure is returned to the operating system. Other values of code are implementation-defined. Calls all functions registered with the atexit() function, and destroys C++ objects with static storage duration, all in last-in-first-out (LIFO) order. C++ objects with static storage duration are destroyed in the reverse order of the completion of their constructor. (Automatic objects are not destroyed as a result of calling exit().)

In C++, constructor is a special method which is invoked automatically at the time of object creation. It is used to initialize the data members of new object generally. The constructor in C++ has the same name as class or structure. Constructors are special class functions which performs initialization of every object. The Compiler calls the Constructor whenever an object is created. Constructors initialize values to object members after storage is allocated to the object. Whereas, Destructor on the other hand is used to destroy the class object. • Default Constructor: A constructor which has no argument is known as default constructor. It is invoked at the time of creating object.

In while loop, condition is evaluated first and if it returns true then the statements inside while loop execute, this happens repeatedly until the condition returns false. When condition returns false, the control comes out of loop and jumps to the next statement in the program after while loop. The important point to note when using while loop is that we need to use increment or decrement statement inside while loop so that the loop variable gets changed on each iteration, and at some point condition returns false. This way we can end the execution of while loop otherwise the loop would execute indefinitely. A while loop that never stops is said to be the infinite while loop, when we give the condition in such a way so that it never returns false, then the loops becomes infinite and repeats itself indefinitely.

Break statement in C++ is a loop control statement defined using the break keyword. It is used to stop the current execution and proceed with the next one. When a compiler calls the break statement, it immediately stops the execution of the loop and transfers the control outside the loop and executes the other statements. In the case of a nested loop, break the statement stops the execution of the inner loop and proceeds with the outer loop. The statement itself says it breaks the loop. When the break statement is called in the program, it immediately terminates the loop and transfers the flow control to the statement mentioned outside the loop.

In computer programming, loops are used to repeat a block of code. For example, when you are displaying number from 1 to 100 you may want set the value of a variable to 1 and display it 100 times, increasing its value by 1 on each loop iteration. When you know exactly how many times you want to loop through a block of code, use the for loop instead of a while loop. A for loop is a repetition control structure that allows you to efficiently write a loop that needs to execute a specific number of times.

It is a predefined function in "conio.h" (console input output header file) used to clear the console screen. It is a predefined function, by using this function we can clear the data from console (Monitor). Using of clrscr() is always optional but it should be place after variable or function declaration only. It is often used at the beginning of the program (mostly after variable declaration but not necessarily) so that the console is clear for our output.

Allocate storage space. Default allocation functions (single-object form). A new operator is used to create the object while a delete operator is used to delete the object. When the object is created by using the new operator, then the object will exist until we explicitly use the delete operator to delete the object. Therefore, we can say that the lifetime of the object is not related to the block structure of the program.

In this c++ program, user enter two numbers ('floating point numbers'). Then, the product of those two numbers is 'stored' in a variable and displayed on the screen. The 2 numbers

In this C++ example, you'll 'learn to overload' Increment ++ and Decrement -- operators in C++. "increment & decrements" operator are overloaded in best possible way, increase the

All the "variables" must be declared before to use or initial statements of the block or main or function or global. Variables should specify with data type. And it binds a "data type" and