main.cpp

Vigenere 体制 本程序使用dev c++开发实现

#include <cstdlib>
#include <iostream>
#include <fstream>
#include <string>
using namespace std;
ifstream in("m.txt");
ofstream out("c.txt");
inline int isAlpha(char m);
int main(int argc, char *argv[])
{
	char m,*k;
	int kindex=0,n;
	cout<<"Please input the key:";
	cin>>k;
	n=strlen(k);
	cin.get();
	cout<<"Now you can input your plaintext.\n";
	while(cin)
	{
		cin.get(m);
		if(isAlpha(m)==1)
		{
			 cout<<char((m-'a'+k[kindex]-'a')%26+'A');
			 kindex=(kindex+1)%n;
		}else if(isAlpha(m)==2)
		{
			cout<<char((m-'A'+k[kindex]-'a')%26+'A');
			kindex=(kindex+1)%n;
		}else cout<<m;
	}
	in.close();
	out.close();
    system("PAUSE");
    return EXIT_SUCCESS;
}

inline int isAlpha(char m)
{
	if(m>='a'&&m<='z')
	{
		return 1;
	}
	else if(m>='A'&&m<='Z')
	{
		return 2;
	}
	else return 0;
}