Encryption.c

#include<stdio.h>
#include<conio.h>
#include<string.h>
#include<ctype.h>
void main()
{
    char pwd[20];
    char alpha[26]="abcdefghijklmnopqrstuvwxyz";
    int num[20],i,n,key;
    //clrscr();
    printf("\nEnter the password:");
    scanf("%s",&pwd);
    n=strlen(pwd);
    for(i=0;i<n;i++)
        num[i]=toascii(tolower(pwd[i]))-'a';
    printf("\nEnter the key:");
    scanf("%d",&key);
    for(i=0;i<n;i++)
        num[i]=(num[i]+key)%26;
    for(i=0;i<n;i++)
        pwd[i]=alpha[num[i]];
    printf("\nThe key is:%d",key);
    printf("\nEncrypted text is:%s",pwd);
    for(i=0;i<n;i++)
    {
        num[i]=(num[i]-key)%26;
        if(num[i]<0)
            num[i]=26+num[i];
        pwd[i]=alpha[num[i]];
    }
    printf("\nDecrypted text is:%s",pwd);
    getch();
}