我制作了用于密钥 rot7 和 rot13 的小型加密程序。除了两个 6 个字母 uvwxyz 外,一切正常。
如果我输入 ABCDEFGHIJKLMNOPQRSTUVWXYZ 它加密和解密没有问题。但是,如果我用小写字母输入相同的内容,那么 uvwxyz 将不起作用。
话虽如此,我已经允许 ascii 表中的所有可写字符作为有效范围,如下所示:
// allow all writable characters from 32 to 255
if ((str[i] >= 32 ) && (str[i] <=255))
{
str[i] -= key;
}
下面是加密过程:
cout << endl;
cout << "Encrypting process started " << endl << endl;
cout << "--------------------------- " << endl;
//get the string length
int i = 0;
int length = str.length();
int key = rot13 ;
int k = 5;
int multiple = 0;
int count = 0;
cout << "the text to encrypt is: " << str << endl;
cout << "text length is: " << length << endl;
cout << "using rot13"<<endl;
cout <<"---------------------------" << endl;
cout << "using rot13" << endl;
//traverse the string
for(i = 0; i < length; i++)
{
count ++;
cout << left;
//if it is a multiple of 5 not the first character change the key
if((multiple = (( i % 5 ) == 0)) && (count != 1) && (key == rot13)){
key = rot7;
}
//if it is a multiple of 5 not the first character change the key
else if((multiple = (( i % 5 ) == 0)) && (count != 1) && (key == rot7) ) {
key = rot13;
}
// Capital letters are 65 to 90 (a - z)
if ((str[i] >= 32) && (str[i] <= 255))
{
str[i] += key;
}
}
return str;
如果我允许这个范围,大写字母怎么可能起作用而不是小写字母?会不会是因为别的原因?我已经将这些捕获添加到一步一步发生的事情中......希望这会有所帮助