#include<stdio.h>
#include<stdlib.h>


typedef struct linklist{
    int val;
    struct linklist *next;
} MyLinkedList;

MyLinkedList* myLinkedListCreate() {
    MyLinkedList* obj = (MyLinkedList* ) malloc(sizeof(MyLinkedList));
    obj->val=1001;
    obj->next=NULL;
    printf("build up successful\n");
    return obj;
}

void check(MyLinkedList* obj){
    MyLinkedList* look =(MyLinkedList* ) malloc(sizeof(MyLinkedList));
    look=obj;
    while(look !=NULL){
        printf("%d -> ",look->val);
        look=look->next;
    }
    printf("NULL\n");
    
}

void myLinkedListAddAtHead(MyLinkedList* obj, int val) {
        if(obj==NULL || obj->val==1001) {
        
        obj->val=val;
        obj->next=NULL;
        printf("initial addhead %d\n",obj->val);
    }
    else {
        MyLinkedList* tem = (MyLinkedList* )malloc(sizeof(MyLinkedList));
        // tem->val=obj->val;
        // tem->next=obj->next;
        // obj->val=val;
        // obj->next=tem;
        tem->val=val;
        tem->next=obj;
        obj=tem;

        printf("obj & obj next %d %d %d %d\n",obj->val,obj->next->val,&obj,&(obj->next));
        printf("tem & tem next %d %d %d %d\n",tem->val,tem->next->val,&tem,&(tem->next));
        printf("addhead %d\n",obj->val);
        check(obj);
    }
}

int main(){
    MyLinkedList* obj=myLinkedListCreate();
    printf("step1\n");
    myLinkedListAddAtHead(obj,7);
    printf("\nstep2\n");
    myLinkedListAddAtHead(obj,2);
    printf("\nstep3\n");
    myLinkedListAddAtHead(obj,1);

}
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Read inputs from stdin

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#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
}