This program is for implementing Mono-Alphabetic Encryption .
#include<stdio.h>
#include<conio.h>
void main()
{
char str[100],ckey[3];
int encr[100],key;
int i,j,k,tmp;
clrscr();
printf("Enter String : ");
gets(str);
printf("Enter key : ");
gets(ckey);
k=ckey[0];
if(k>=49 && k<=58)
{
key=0;
k=strlen(ckey);
for(i=0;i<k;i++)
{
tmp=ckey[i]-48;
tmp=tmp%10;
key=(key*10)+tmp;
}
}
if(k>=65 && k<=90)
{
key=1;
tmp=65;
while(tmp!=k)
{
key++;
tmp++;
}
}
if(k>=97 && k<=123)
{
key=1;
tmp=97;
while(tmp!=k)
{
key++;
tmp++;
}
}
for(i=0;str[i]!='\0';i++)
{
if(str[i]>=65 && str[i]<=90)
{
encr[i]=str[i]+key;
if(encr[i]>90)
{
j=encr[i]-90;
encr[i]=64+j;
}
}
else
{
encr[i]=str[i]+key;
if(encr[i]>122)
{
j=encr[i]-122;
encr[i]=96+j;
}
}
printf("%c",encr[i]);
}
getch();
}
#include<stdio.h>
#include<conio.h>
void main()
{
char str[100],ckey[3];
int encr[100],key;
int i,j,k,tmp;
clrscr();
printf("Enter String : ");
gets(str);
printf("Enter key : ");
gets(ckey);
k=ckey[0];
if(k>=49 && k<=58)
{
key=0;
k=strlen(ckey);
for(i=0;i<k;i++)
{
tmp=ckey[i]-48;
tmp=tmp%10;
key=(key*10)+tmp;
}
}
if(k>=65 && k<=90)
{
key=1;
tmp=65;
while(tmp!=k)
{
key++;
tmp++;
}
}
if(k>=97 && k<=123)
{
key=1;
tmp=97;
while(tmp!=k)
{
key++;
tmp++;
}
}
for(i=0;str[i]!='\0';i++)
{
if(str[i]>=65 && str[i]<=90)
{
encr[i]=str[i]+key;
if(encr[i]>90)
{
j=encr[i]-90;
encr[i]=64+j;
}
}
else
{
encr[i]=str[i]+key;
if(encr[i]>122)
{
j=encr[i]-122;
encr[i]=96+j;
}
}
printf("%c",encr[i]);
}
getch();
}