试试

#include "stdafx.h" int _tmain(int argc, _TCHAR* argv[]) { char str[100]; cout<<"请输入你想要生成的凯撒密码："<<endl; cin>>str; cout<< "你输入的是："<<str<<endl; int i=0; while(str[i]!=0) { if(str[i]>='a'&&str[i]<='w') str[i]=str[i]+'A'-'a'+3;   // +'A'-'a'+3  =29 else if(str[i]>='A'&&str[i]<='W') str[i]+=3; else if(str[i]>='x'&&str[i]<='z') str[i]=str[i]-'x'+'A'; else if(str[i]>='X'&&str[i]<='Z') str[i]=str[i]-'x'+'A'; i++; } cout<<"加密后是内容是："<<str<<endl; system("pause"); return 0; }