//WRITE A PROGRAM TO SIMULATE DEADLOCK BETWEEN THREE THREADS
#include<stdio.h>
#include<pthread.h>
#include<unistd.h>
void *function1();
void *function2();
void *function3();
pthread_mutex_t first_mutex; //MUTEX LOCK
pthread_mutex_t second_mutex;
pthread_mutex_t third_mutex;

int main()
{
pthread_mutex_init(&first_mutex,NULL); //INITIALIZE THE LOCK
pthread_mutex_init(&second_mutex,NULL);
pthread_mutex_init(&third_mutex, NULL);
pthread_t one, two, three;
pthread_create(&one, NULL, function1, NULL); //CREATE THREAD
pthread_create(&two, NULL, function2, NULL);
pthread_create(&three, NULL, function3, NULL);
pthread_join(one, NULL);
pthread_join(two, NULL);
pthread_join(three, NULL);
printf("Thread joined\n");
}
void *function1( )
{
pthread_mutex_lock(&first_mutex); //TO ACQUIRE THE RESOURCE/MUTEX LOCK
printf("Thread ONE Acquired first_mutex\n");
sleep(1);
pthread_mutex_lock(&second_mutex);
printf("Thread ONE Acquired second_mutex\n");
pthread_mutex_unlock(&second_mutex); //TO RELEASE THE RESOURCE
printf("Thread ONE Released second_mutex\n");
pthread_mutex_unlock(&first_mutex);
printf("Thread ONE Released first_mutex\n");
}

void *function2( )
{
pthread_mutex_lock(&second_mutex);
printf("Thread TWO Acquired second_mutex\n");
sleep(1);
pthread_mutex_lock(&third_mutex);
printf("Thread TWO Acquired third_mutex\n");
pthread_mutex_unlock(&third_mutex);
printf("Thread TWO Released third_mutex\n");
pthread_mutex_unlock(&second_mutex);
printf("Thread TWO Released second_mutex\n");
}

void *function3( )
{
pthread_mutex_lock(&third_mutex);
printf("Thread THREE Acquired third_mutex\n");
sleep(1);
pthread_mutex_lock(&first_mutex);
printf("Thread THREE Acquired first_mutex\n");
pthread_mutex_unlock(&first_mutex);
printf("Thread THREE Released first_mutex\n");
pthread_mutex_unlock(&third_mutex);
printf("Thread THREE Released third_mutex\n");
}
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#include <stdio.h>
int main()
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    char name[50];
    printf("Enter name:");
    scanf("%s", name);
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    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
}