#include<stdio.h>
#include<stdlib.h>
struct Node;
typedef struct Node * PtrToNode;
typedef PtrToNode List;
typedef PtrToNode Position;

struct Node
{
	int e;
	Position next;
};

void Insert(int x, List l, Position p)
{
	Position TmpCell;
	TmpCell = (struct Node*) malloc(sizeof(struct Node));
	if(TmpCell == NULL)
		printf("Memory out of space\n");
	else
	{
		TmpCell->e = x;
		TmpCell->next = p->next;
		p->next = TmpCell;
	}
}


int isLast(Position p, List l)
{
	return (p->next == l);
}

Position FindPrevious(int x, List l)
{
	Position p = l;
	while(p->next != l && p->next->e != x)
		p = p->next;
	return p;
}

Position Find(int x, List l)
{
	Position p = l->next;
	while(p != l && p->e != x)
		p = p->next;
	return p;
}

void Delete(int x, List l)
{
	Position p, TmpCell;
	p = FindPrevious(x, l);
	if(!isLast(p, l))
	{
		TmpCell = p->next;
		p->next = TmpCell->next;
		free(TmpCell);
	}
	else
		printf("Element does not exist!!!\n");
}

void Display(List l)
{
	printf("The list element are :: ");
	Position p = l->next;
	while(p != l)
	{
		printf("%d -> ", p->e);
		p = p->next;
	}
}

int main()
{
	int x, pos, ch, i;
	List l, l1;
	l = (struct Node *) malloc(sizeof(struct Node));
	l->next = l;
	List p = l;
	printf("CIRCULAR LINKED LIST IMPLEMENTATION OF LIST ADT\n\n");
	do
	{
		printf("\n\n1. INSERT\t 2. DELETE\t 3. FIND\t 4. PRINT\t 5. QUIT\n\nEnter the choice :: ");
		scanf("%d", &ch);
		switch(ch)
		{
			case 1:
				p = l;
				printf("Enter the element to be inserted :: ");
				scanf("%d",&x);
				printf("Enter the position of the element :: ");
				scanf("%d",&pos);
				for(i = 1; i < pos; i++)
				{
					p = p->next;
				}
				Insert(x,l,p);
				break;

			case 2:
				p = l;
				printf("Enter the element to be deleted :: ");
				scanf("%d",&x);
				Delete(x,p);
				break;

			case 3:
				p = l;
				printf("Enter the element to be searched :: ");
				scanf("%d",&x);
				p = Find(x,p);
				if(p == l)
					printf("Element does not exist!!!\n");
				else
					printf("Element exist!!!\n");
				break;

			case 4:
				Display(l);
				break;
		}
	}while(ch<5);
	return 0;
}
by

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Read inputs from stdin

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

#include <stdio.h>
int main()
{
    char name[50];
    printf("Enter name:");
    scanf("%s", name);
    printf("Hello %s \n" , name );
    return 0;
    
}

About C

C language is one of the most popular general-purpose programming language developed by Dennis Ritchie at Bell laboratories for UNIX operating system. The initial release of C Language was in the year 1972. Most of the desktop operating systems are written in C Language.

Key features:

  • Structured Programming
  • Popular system programming language
  • UNIX, MySQL and Oracle are completely written in C.
  • Supports variety of platforms
  • Efficient and also handle low-level activities.
  • As fast as assembly language and hence used as system development language.

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);

Arrays

Array is a collection of similar data which is stored in continuous memory addresses. Array values can be fetched using index. Index starts from 0 to size-1.

Syntax

One dimentional Array:

data-type array-name[size];

Two dimensional array:

data-type array-name[size][size];

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.

Two types of functions are present in C

  1. Library Functions:

Library functions are the in-built functions which are declared in header files like printf(),scanf(),puts(),gets() etc.,

  1. User defined functions:

User defined functions are the ones which are written by the programmer based on the requirement.

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
}