#include??
#include?
#include??
#include??
#include??
#include?
#include
using?namespace?std;
void?Shift（）?/*移位密碼*/?
{?
	char?c[100];?
	int?length?i=0?key=0;?
	////clrscr（）;?
????
	printf（“********使用凱撒加密********\n請輸入要加密內容:\n?“）;?
	cin?>>?c;?
	printf（“********使用凱撒加密********\n請輸入你的密鑰（必須是整數）：\n?“）;?
	scanf（“%d“&key）;
	length?=?strlen（c）;?
	for（i=0;?i	{?
		if（c[i]>=‘A‘&&c[i]<=‘Z‘）?
			c[i]?=?（c[i]+key-‘A‘）%26+‘A‘;?
		else?if（c[i]>=‘a‘&&c[i]<=‘z‘）?
			c[i]?=?（c[i]+key-‘a‘）%26+‘a‘;?
	}?
	printf（“密文:?%s\n“?c）;?
	printf（“按任意鍵返回\n“）;?
	getch（）;?
}?

int?gcd（int?a?int?b）?/*輾轉相除法求ab的最大公因數*/?
{?
	int?k?=?0;?

	do?
	{?
		k?=?a%b;?
		a?=?b;?
		b?=?k;?
	}while（k!=0）;?
	return?a;?
}?

int?Ni（int?a?int?b）?/*求a相對于b的逆*/?
{?
	int?i?=?0;?
	while（a*（++i）%b!=1）;?
	return?i;?
}?

void?DeShift（）?/*凱撒密碼解密*/?
{?
	char?c[100];?
	int?length?i=0?key=7;?
	////clrscr（）;?

	printf（“********使用凱撒解密********\n請輸入要解密內容:\n“）;?
	cin?>>?c;?
	printf（“密文:?%s\n“?c）;?
	printf（“********使用凱撒解密********\n請輸入你的密鑰（必須是整數）:\n“）;?
	scanf（“%d“&key）;
	length?=?strlen（c）;?
	for（i=0;?i	{?
		if（c[i]>=‘A‘&&c[i]<=‘Z‘）?
			c[i]?=?（c[i]-key+26-‘A‘）%26+‘A‘;?
		else?if（c[i]>=‘a‘&&c[i]<=‘z‘）?
			c[i]?=?（c[i]-key+26-‘a‘）%26+‘a‘;?
	}?
	printf（“明文:?%s\n“?c）;?
	printf（“按任意鍵返回...\n“）;?
	getch（）;?
}?

void?Vigenere（）?/*維吉利亞密碼*/?
{?
????const?int?M=30;
????int?m=0n=0;
????char?p[M];
????char?k[M];
????char?c[M];

	cout<<“********維吉利亞加密********\n請輸入要加密內容:（按#號結束）:“<?????????int?i=0;
?????????cin>>p[i];
?????????for（i=1;i?????????????????????m++;
?????????????????????cin>>p[i];}
?????????
??????????int?plen=i-1;?
??????cout<<“key：（按#號結束）:“<????????i=0;
?????????cin>>k[i];
????????
????????for（i=1;i?????????????????????n++;
?????????????????????cin>>k[i];}?
		int?pwlen=i-1;
???cout<<“密文:“<???for（int?i=0j=0;i		j=i%pwlen;?????????????????????
??????if（p[i]==‘?‘）{
???????i++;
???????m--;
????????continue;}
??????else{
?????????if（p[i]>=‘A‘&