How to reverse a string using pointer or array in cpp without using strrev library function

How to reverse a string using pointer or array. CPP program for reversing a strings without using inbuilt library function strrev. How to reverse a sentence in cpp/C++/C without using library function strrev.Program to reverse a string using pointer.
#include<stdio.h>
#include<string.h>
int main()
{
char arr1[20];
printf("Enter a String:\n");
scanf("%s",&arr1);
printf("You entered:%s\n",arr1);

CPP program for concatenating two strings without using inbuilt library function strcat

How to concatenate two strings using pointer or array. CPP program for concatenating two strings without using inbuilt library function strcat. How to concatenate two strings in cpp/C++/C without using inbuilt in function strcat.Program to concatenate two strings using pointer.

#include<stdio.h>
#include<string.h>
int main()
{
char arr1[20];
printf("Enter a String:\n");
scanf("%s",&arr1);

How to search a substring in C++/Cpp without using library function strstr

/*How to search a sub string without using library function strstr. 
How to use pointer/array to search substring in a string sentence.

C++/CPP/C program/code to search a word in a sentence without using inbuilt function strstr*/

#include<stdio.h>

#include<string.h>

int main()

{

char arr1[50];

printf("Enter a String:\n");

scanf("%s",&arr1);

char arr2[20];

printf("Enter a String:\n");

scanf("%s",&arr2);

printf("Searching for:%s\n",arr2);

How to use make file in CPP C+++ C

/*What is makefile  ?
---------------------------------------
makefile is a script/utility  that contains target, dependencies and actions to compile modified file/files in a project of multple files.  */

/*SYNTAX
-----------------------------------
target:dependencies
[tab]  actions
.
.

How to implement msgq message queue in CPP C C++

//Program to implement msgq

/*CPP Program for msg queue in Linux

pipes work with related process parent-child only.

Fifo can make unrelated process to communicate but

fifo created does not persists for use in future.

Shared memory is similar to fifo but over comes this and can be used later also.

Program to implement IPC Message Queues IPC mechanism.

msgqSendkirk.c adds the message on the message queue.

msgqRecvSpock.c reads and removes the message from the message

queue.To use this program first compile and run msgqSendkirk.c

to add a message to the message queue. To see the

Message Queue in other terminal run msgqRecvSpock.c

ipcs -q shows the msg ques.

ipcrm -q 131073 removes the msgq created say 131071 */

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

#include <errno.h>

#include <string.h>

#include <sys/types.h>

#include <sys/ipc.h>

#include <sys/msg.h>

//1. declaring the msg structure

struct my_msgbuf

{