Vignar Cipher in C

/* Program to implement Vignar Cipher */

#include<stdio.h>

#include<string.h>

int strlen(char a[])

{

int i=0;

for(i=0;a[i]!='\0';i++);

return i;

}

int main()

{

char text[20];

int i,j;

int k[]={4,8,6,9,6,6,1,9};

printf("Enter String\n");

scanf("%s",text);

for(i=0,j=0;i

{

if(j==8)

j=0;

text[i]=text[i]+k[j];

if(text[i]>122)

{

text[i]=text[i]-26;

}

else if(text[i]>90 && text[i]<97)

text[i]=text[i]-26;

else if(text[i]>57 && text[i]<65)

text[i]=text[i]-10;

else

{}

}

printf("Cipher Text is %s",text);

for(i=0,j=0;i

{

if(j==8)

j=0;

text[i]=text[i]-k[j];

if(text[i]<97)

text[i]+=26;

}

printf("\nDecrypt Text is %s",text);

return 0;

}

/* Output */

Enter your email address:
Delivered by FeedBurner