Zoj 1006 Encryption

// Non-redundant Encryption
// Because the divisor and remainder are the same, and both are smaller than 28, the MOD is the same for each other.
# Include <iostream>
# Include <string>
Using namespace STD;
Char st [2, 100], en [2, 100];
Int stnum [100], ennum [100];

 

Int main ()
{
Int I, K, Len, Pos;
While (CIN> K & K! = 0)
{
Cin> st;
Len = strlen (ST );
For (I = 0; I <Len; I ++)
{
If (ST [I] = '.')
Stnum [I] = 27;
Else if (ST [I] = '_')
Stnum [I] = 0;
Else
Stnum [I] = sT [I]-'A' + 1;
}
For (I = 0; I <Len; I ++)
{
Pos = (k * I) % Len;
Ennum [POS] = (stnum [I] + I) % 28;
}

For (I = 0; I <Len; I ++)
{
If (ennum [I] = 27)
En [I] = '.';
Else if (ennum [I] = 0)
En [I] = '_';
Else
En [I] = ennum [I]-1 + 'a ';
}

for (I = 0; I cout cout }< br> return 0;
}