C program to reverse string using recursion

#include<stdio.h>
void reverse(char*,int,int);

int main()
{
char a[100];
gets(a);
reverse(a,0,strlen(a)-1);
printf("%s\n",a);
return 0;
}

void reverse(char *x,int i,int j)
{
char c;
if(i>=j)
return;
c=*(x+i);
*(x+i)=*(x+j);
*(x+j)=c;

reverse(x,++i,--j);
}

Management Information System Student Resources - Online MCQ Collection

Management Information System Student Resources

Cryptography

Cryptography is the practice and study of hiding information. It is also called the code, but this is not really a good name. It is a science that is used to keep the information confidential and secure. Modern cryptography is a mix of mathematics, computer science and electrical engineering. Cryptography is used in ATM (banking) cards, computer passwords, and shopping on the internet.

If a message is sent is changed with cryptography (or encrypted) before it is sent. The method of changing the text is a "code" or, rather, as a “cipher”. The amended text is "tagged”. The amendment makes the message difficult to read. Someone who wants to read it should change back (or decrypt). How to change back it's a secret. Both the individual sending the message and the one who receives must change the secret way to know, but others may not. Studying the cypher text called to discover the secret “cryptanalysis” or “cracking" or sometimes “code breaking”.

Different types of cryptography can be easier or harder to use and can be better or worse hide the secret message. Figures use a "key" that is a secret hiding secret messages. The cryptographic method does no secret. Different people may have the same method, but using different keys so that they cannot read each others messages. Since Caesar cipher that so many keys as the number of letters in the alphabet easily cracked by trying all the keys. Figures billions of keys can be cracked by more complex methods.

References

Understanding Cryptography: A Textbook for Students and Practitioners By Christof Paar, Jan Pelzl

Cryptography: Theory and Practice, Third Edition By Douglas R. Stinson

More Books

Computer Viruses

Software Development Life Cycle(SDLC) Vidio Tutorial

CASE Tools

Spiral Model

System Development Life Cycle-SDLC

Sample C Questions & Answers

C Questions & Answers

Binary search implementation using C language

#include<stdio.h>
#include<conio.h>
#define MAX 20

int bsearch(int [],int,int,int);

void main()
{
int a[10],i,t,f=0,n,l,k;
int bsearch(int[],int,int,int);
clrscr();
printf("\n\nEnter the size of an array: ");
scanf("%d",&n);

if (n>MAX)
{
printf("\nInvalid Index\n");
}
else
{
printf("\nEnter the array elements:\n");
}

    for(i=0;i<n;i++)
    {
    scanf("%d",&a[i]);
    }

printf("\n\n Enter element for search: ");
scanf("%d",&t);
l=n-1;
k=bsearch(a,f,l,t);

    if(k==-1)
    {
    printf("\n Element is not found\n");
    }
    else
    {
    printf("\n\nElement is found at location: %d",k);
    }

getch();
}

int bsearch(int list[],int f,int l,int t)//Binary Search function implementation
{
int m;
    while(f<=l)
    {
    m=(f+l)/2;
       
        if(list[m]==t)
        {
        return m;
        }
            else if(t<list[m])
            {
            l=m-1;
            }
                else if(t>list[m])
                {
                f=m+1;
                }
    }
return(1);
}

Linear Search Implementation Using C language

#include <stdio.h>
int linearsearch(int*,int,int);

int main()
{
int array[50],search,c,n,position;
clrscr();
printf("Enter thE number of elements in array\n");
scanf("%d",&n);
printf("Enter %d numbers\n",n);

    for(c=0;c<n;c++)
  
    scanf("%d",&array[c]);
    }

printf("Enter the number to search\n");
scanf("%d",&search);

position=linersearch(array,n,search);
    if(position==-1)
    {
    printf("%d is not present in array\n",search);
    }
    else
    {
    printf("%d is present at location %d\n",search,position+1);
    }
getch();
return 0;
}

int linersearch(int *pointer,int n,int find)//Implementation of linersearch

function
{
int c;
    for(c=0;c<n;c++)
    {
        if(*(pointer+c)==find)
    {
    return c;
    }
}
return -1;
}