casa.cpp

替代密码包括多种类型

#include<iostream.h>
#include<stdio.h>
char Caesar( char &c , int d ) ;
int main()
{    int k;
	char c;
cout<<"Please input the k= ";
cin>>k;
	while((c=getchar())!='\n')
	{
		if((c>='a'&&c<='z')||(c>='A'&&c<='Z'))
		{
			c=Caesar(c,k);
			if(c>'Z'&&c<='Z'+k||c>'z') c=c-26;
		}
		cout<<c;
	}
	cout<<endl;
	return 0;
}

char Caesar( char &c , int k ) 
{
    char t ; 

    k %= 26 ;
    t = c + k ;
    if( t > 'z' )
        t -= 26 ;
    if ( ( c <= 'Z' ) && ( c + k > 'Z' ) )
        t -= 26 ;
    return t ;
}