#include <stdio.h>
#include <stdlib.h>
// Definition of a singly linked list node
struct ListNode {
int val;
struct ListNode* next;
};
// Function to merge two sorted linked lists (recursive approach)
struct ListNode* mergeTwoLists(struct ListNode* list1, struct ListNode*
list2) {
// Base case: If either list1 or list2 is NULL, return the other list
if (list1 == NULL) {
return list2;
}
if (list2 == NULL) {
return list1;
}
// Compare the values of the current nodes in list1 and list2
if (list1->val < list2->val) {
// Select list1's current node as the current node in the merged list
list1->next = mergeTwoLists(list1->next, list2);
return list1;
} else {
// Select list2's current node as the current node in the merged list
list2->next = mergeTwoLists(list1, list2->next);
return list2;
}
}
// Function to create a new node with the given value
struct ListNode* createNode(int val) {
struct ListNode* newNode = (struct ListNode*)malloc(sizeof(struct
ListNode));
newNode->val = val;
newNode->next = NULL;
return newNode;
}
// Function to insert a new node at the end of the linked list
void insertAtEnd(struct ListNode head, int val) {
struct ListNode* newNode = createNode(val);
if (*head == NULL) {
head = newNode;
} else {
struct ListNode* current = head;
while (current->next != NULL) {
current = current->next;
}
current->next = newNode;
}
}
// Function to print a linked list
void printList(struct ListNode* head) {
struct ListNode* current = head;
while (current != NULL) {
printf("%d -> ", current->val);
current = current->next;
}
printf("NULL\n");
}
int main() {
// Create two sorted linked lists
struct ListNode* list1 = NULL;
struct ListNode* list2 = NULL;
insertAtEnd(&list1, 1);
insertAtEnd(&list1, 3);
insertAtEnd(&list1, 5);
insertAtEnd(&list2, 2);
insertAtEnd(&list2, 4);
insertAtEnd(&list2, 6);
// Print the input lists
printf("List 1: ");
printList(list1);
printf("List 2: ");
printList(list2);
// Merge the two lists
struct ListNode* mergedList = mergeTwoLists(list1, list2);
// Print the merged list
printf("Merged List: ");
printList(mergedList);
// Free the memory allocated for the merged list
struct ListNode* current = mergedList;
while (current != NULL) {
struct ListNode* temp = current;
current = current->next;
free(temp);
}
return 0;
}

C Language online compiler

Write, Run & Share C Language code online using OneCompiler's C online compiler for free. It's one of the robust, feature-rich online compilers for C language, running the latest C version which is C18. Getting started with the OneCompiler's C editor is really 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 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
}