#include<stdio.h>
#include<unistd.h>
#include<string.h>
main()
{
 int p1[2],p2[2],p3[2],p4[2];
 int i,j=0,k=0,l=0;
 char r[10],s[10],t[10],u[10];
 printf("\t PROCESS 1.ENTER THE STRING");
 scanf("%s",r);
 pipe(p1);
 pipe(p2);
 write(p1[1],r,sizeof(r));
 write(p2[1],r,sizeof(r));
 int a=fork();
 if(a==0)
 {
  printf("\n\t PROCESS 2:it splits the given string\n");
  read(p1[0],r,sizeof(r));
  int n=strlen(r);
  for(i=0;i<n/2;i++)
  {
    s[i]=r[i];
  }
  for(i=n/2;i<=n;i++)
  {
   t[j++]=r[i];
  }
  pipe(p3);
  pipe(p4);
  write(p3[1],s,sizeof(s));
  write(p4[1],t,sizeof(t));
  int b=fork();
  if(b==0)
  {
   printf("p4 %d\t",getpid());
   printf("p2 %d\n",getppid());
   read(p3[0],s,sizeof(s));
   printf("\t PROCESS 4:sub string \t %s \t",s);
   printf("no of char=%d \n",strlen(s));
  }
  else
  {
    int c=fork();
    if(c==0)
  {
   printf("p5 %d\t",getpid());
   printf("p2 %d\n",getppid());
   read(p4[0],t,sizeof(t));
   printf("\t PROCESS 5:sub string \t %s \t",t);
   printf("no of char=%d \n",strlen(t));
  }
  else
  {
    wait();
    printf("p2 %d\t",getpid());
    printf("p1 %d\n",getppid());
  }   }}
else
{
  wait();
  int d=fork();
  if(d==0)
   {
     printf("p3 %d\t",getpid());
     printf("p1 %d\n",getppid());
     read(p2[0],r,sizeof(r));
     for(i=strlen(r)-1;i>=0;i--)
     {
       u[l++]=r[i];
     }
     for(i=0;i<strlen(r);i++)
     {
       if(u[i]==r[i])
       k++;
       else
       continue;
    }
     if(k==strlen(r))
     printf("\t PROCESS 3: the given string is palindrome\n");
     else
     printf("\t PROCESS 3: the given string is not palindrome\n");
    }
    else
    {
      printf("p1 %d\t",getpid());
      printf("kernal %d\t\n",getppid());
    }
 }}

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
}