main()
{
int a,j;
// get string
string words;
cout<<"请输入您1要破译的密码:";
cin >> words;
// get length
a = words.length();
cin.clear();
cout<<"请输入加密数字的值:(如果无请填0)";
cin >> j;
if (j<27 && j>0 )
{
for (int i = 0; i < a; i++)
{
char ch = words[i];
if (ch == ' ') cout<<" ";//判断空格
else if (int(ch)-j < 97)
{
ch=ch+26-j;
}
else ch-=j;
cout<
}