zhihuan.cpp

C++描述置换密码 源码 标题要长长长长长长长长长长长长长长长长长长长长

#include "iostream.h"
int main()
{
	void encrupt(char *,int *,int);
	void decrupt(char *,int *,int);
	cout<<"置换密码演示"<<endl;
	int n,p;
	cout<<"输入密钥长度：";
	cin>>n;
	int *key=new int[n];
	cout<<"输入密钥：";
	for(int i=0;i<n;i++)
	    cin>>key[i];
	int *keyni=new int[n];
	for(i=0;i<n;i++)
		keyni[key[i]-1]=i+1;
    while(true)
	{
		cout<<"如果加密，输入1；如果解密，输入2；否则输入其它数：";
		cin>>p;
		if(p!=1 && p!=2)
			return 0;
		char message[50];
		if(p==1)
			cout<<"输入明文：";
		else cout<<"输入密文：";
		cin>>message;
		for(i=0;message[i]!=0;i++);
		while(i%n!=0)
			message[i++]='?';
		message[i]=0;
		if(p==1)
			encrupt(message,key,n);
		else
			decrupt(message,keyni,n);
	}
	delete []key;
	delete []keyni;
	return 0;
}
void encrupt(char *message,int *key,int n)
{
	char transmit[50],k;
	int j=0;
	for(int i=0;message[i]!=0;i++)
	{
		k=message[key[i%n]-1+i/n*n];
		if(k=='?') continue;
		else transmit[j++]=k;
	}
	transmit[j]=0;
	cout<<"密文为：  "<<transmit<<endl;
}
void decrupt(char *message,int *keyni,int n)
{
	char transmit[50],k;
	int j=0;
	for(int i=0;message[i]!=0;i++)
	{
		k=message[keyni[i%n]-1+i/n*n];
		if(k=='?') continue;
		else transmit[j++]=k;
	}
	transmit[j]=0;
	cout<<"明文为：  "<<transmit<<endl;
}