 #include <iostream.h>
#include <conio.h>

int f = -1, r = -1;

int IsFull(int queue[]) {
    if ((r + 1) % 5 == f) {
        return 1;
    } else {
        return 0;
    }
}

int IsEmpty(int queue[]) {
    if (f == -1 && r == -1) {
        return 1;
    } else {
        return 0;
    }
}

void enqueue(int queue[], int x) {
    if (IsFull(queue)) {
        cout << "The queue is full." << endl;
    } else if (IsEmpty(queue)) {
        f = 0;
        r = 0;
    } else {
        r = (r + 1) % 5;
    }
    queue[r] = x;
}

void dequeue(int queue[]) {
    if (IsEmpty(queue)) {
        cout << "The queue is empty." << endl;
    } else if (f == r) {
        f = -1;
        r = -1;
    } else {
        f = (f + 1) % 5;
    }
}

void display(int queue[]) {
    if (IsEmpty(queue)) {
        cout << "The queue is empty." << endl;
    } else {
        if (r >= f) {
            for (int i = f; i <= r; i++) {
                cout << queue[i] << endl;
            }
        } else {
            for (int i = f; i < 5; i++) {
                cout << queue[i] << endl;
            }
            for (i = 0; i <= r; i++) {
                cout << queue[i] << endl;
            }
        }
    }
}

void main() {
    clrscr();
    int Q[5];
    int ch, t;
    cout << "1) Enqueue 2) Dequeue 3) Display 4) Exit" << endl;
    do {
        cout << "Enter Choice: ";
        cin >> ch;
        switch (ch) {
            case 1:
                cout << "Enter Value: ";
                cin >> t;
                enqueue(Q, t);
                break;
            case 2:
                dequeue(Q);
                break;
            case 3:
                display(Q);
                break;
            case 4:
                break;
            default:
                cout << "Enter Valid Choice.";
        }
    } while (ch != 4);
    getch();
}

created 1 year ago by MADMAX

C++ Online Compiler

Write, Run & Share C++ code online using OneCompiler's C++ online compiler for free. It's one of the robust, feature-rich online compilers for C++ language, running on the latest version 17. Getting started with the OneCompiler's C++ compiler is simple and pretty fast. The editor shows sample boilerplate code when you choose language as C++ and start coding!

Read inputs from stdin

OneCompiler's C++ online compiler supports stdin and users can give inputs to programs using the STDIN textbox under the I/O tab. Following is a sample program which takes name as input and print your name with hello.

#include <iostream>
#include <string>
using namespace std;

int main() 
{
    string name;
    cout << "Enter name:";
    getline (cin, name);
    cout << "Hello " << name;
    return 0;
}

About C++

C++ is a widely used middle-level programming language.

Supports different platforms like Windows, various Linux flavours, MacOS etc
C++ supports OOPS concepts like Inheritance, Polymorphism, Encapsulation and Abstraction.
Case-sensitive
C++ is a compiler based language
C++ supports structured programming language
C++ provides alot of inbuilt functions and also supports dynamic memory allocation.
Like C, C++ also allows you to play with memory using Pointers.

Syntax help

Loops

1. If-Else:

When ever you want to perform a set of operations based on a condition If-Else is used.

if(conditional-expression) {
   //code
}
else {
   //code
}

You can also use if-else for nested Ifs and If-Else-If ladder when multiple conditions are to be performed on a single variable.

2. Switch:

Switch is an alternative to If-Else-If ladder.

switch(conditional-expression){    
case value1:    
 // code    
 break;  // optional  
case value2:    
 // code    
 break;  // optional  
......    
    
default:     
 code to be executed when all the above cases are not matched;    
}

3. For:

For loop is used to iterate a set of statements based on a condition.

for(Initialization; Condition; Increment/decrement){  
  //code  
}

4. While:

While is also used to iterate a set of statements based on a condition. Usually while is preferred when number of iterations are not known in advance.

while (condition) {  
// code 
}

5. Do-While:

Do-while is also used to iterate a set of statements based on a condition. It is mostly used when you need to execute the statements atleast once.

do {  
 // code 
} while (condition);

Functions

Function is a sub-routine which contains set of statements. Usually functions are written when multiple calls are required to same set of statements which increases re-usuability and modularity. Function gets run only when it is called.

How to declare a Function:

return_type function_name(parameters);

How to call a Function:

function_name (parameters)

How to define a Function:

return_type function_name(parameters) {  
 // code
}