C++实现凯撒密码加解密

密钥为3

//凯撒密码，密钥为3
#include <iostream>
using namespace std;
class code {
public:
	char a[100],b[100];
	void crypto();
	void decrypto();
};
void code::crypto() 
{
	cout << "请输入明文:" << endl;
	cin >> a;
	cout << "密文是:"<<endl;
	for (int i = 0;a[i] != 0;i++) 
	{
		if (a[i] >= 'x' && a[i] <= 'z'||a[i] >= 'X' && a[i] <= 'Z')
			b[i] = a[i] - 23;
		else 
			b[i] = a[i] + 3; 
	cout <<b[i];
	}
	cout << endl;
}
void code::decrypto() 
{
	cout << "请输入密文:" << endl;
	cin >> a;
	cout << "明文是:"<<endl;
	for (int i = 0;a[i] != 0;i++)
	{
		if (a[i] >= &