vigenere密码算法.cpp

用C++实现的维吉尼亚密码源程序,已经在DevC++上测试过

#include<iostream>
#include<math.h>
using namespace std;
const int M=30;
int m=0,n=0;
char p[M];
char k[M];
char c[M];
//input the key and plaintext


                   
int main(){
  
   
     cout<<"Please input the plaintext(end with #):"<<endl;
         int i=0;
         cin>>p[i];
         for(i=1;i<M&&p[i-1]!='#';i++){
                     m++;
                     cin>>p[i];}
             
      cout<<"Please input the key(end with #):"<<endl;   
        i=0;
         cin>>k[i];
        
        for(i=1;i<M&&k[i-1]!='#';i++){
                     n++;
                     cin>>k[i];} 
                        
   for(int i=0,j=0;i<m;i++,j++){
                     
      if(p[i]==' '){
       i++;
       m--;
        continue;}
      else{
         if(p[i]>='A'&&p[i]<='Z'){
           if(k[j]!='#')
                 c[i]=(p[i]-'A'+k[j]-'A')%26+65;
           else{
                j=0;
                c[i]=(p[i]-'A'+k[j]-'A')%26+65;}
                }
         else if(p[i]>='a'&&p[i]<='z'){
           if(k[j]!='#')
                 c[i]=(p[i]-'a'+k[j]-'a')%26+'a';
           else{
                j=0;
                c[i]=(p[i]-'a'+k[j]-'a')%26+'a';}
                }
         else
           cout<<"invalid input!"<<endl;
      cout<<c[i];}}
    cout<<endl;
    system("pause");
}