Affine

#include <iostream>
#include <string>
#include <math.h>
using namespace std;
int main()
{
    string plaintext,encrypt,decrypt;
    int inv;
    cout<<"Enter the message to be encrypted:"<<endl;
    getline(cin,plaintext);
    float a,b;
    cout<<"Enter the values for a and b:"<<endl;
    cin>>a>>b;
    int length=(int)plaintext.length();
    for(int i=0;i<length;i++)
    {
        encrypt[i]=(char)(fmod((a*(plaintext[i]-97)+b),26)+97);
    }
    for(int i=0;i<length;i++)
    {
        if(encrypt[i]=='V')
        {
            cout<<" ";
        }
        else
        {
            cout<<encrypt[i];
        }
    }
    cout<<"\n";
    cout<<"The deciphered text is:"<<endl;
    int f=0;
    inv=0;
    for(int i=0;i<26;i++)
    {
        f=fmod((a*i),26);
        if(f==1)
        {
            inv=i;
        }
    }
    for(int i=0;i<length;i++)
    {
        decrypt[i]=(char)(fmod(inv*((encrypt[i]-97)-b),26)+97);
    }
    for(int i=0;i<length;i++)
    {
        if(decrypt[i]=='T')
        {
            cout<<" ";
        }
        else
        {
            cout<<decrypt[i];
        }
    }
}