Question

跪求高手帮我做一个这个C++加密程序的 解密程序

#include <iostream>

using namespace std;

int main()

{

char ch[100];

int i;

cout<<"请输入一句英文："<<endl;

cin>>ch;

for(i=0;(ch[i]!='\0')&&(i<100);i++)

{

if(((ch[i]>='a')&&(ch[i]<='w'))||

((ch[i]>='A')&&(ch[i]<='W')))

{

ch[i]+=3;

}

else

{

switch(ch[i])

{

case 'x':ch[i]='a';break;

case 'X':ch[i]='A';break;

case 'y':ch[i]='b';break;

case 'Y':ch[i]='B';break;

case 'z':ch[i]='c';break;

case 'Z':ch[i]='C';break;

default:break;

}

}

}

cout<<"加密后："<<endl;

for(i=0;(ch[i]!='\0')&&(i<100);i++)

{

cout<<ch[i];

}

cout<<endl;

return 0;

}

Answer 1

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
const int MAX_N=200;
int main(int argc, char *argv[])
{
int i,j,p;
char text[MAX_N];
char alphabet[30];
char op[10];

while(1)
{
printf("1---输入密码表 2---退出\n");
gets(op);

if(strcmp(op,"1")==0)
{
printf("密码表：");
gets(alphabet);

while(1)
{
printf("1---加密 2---解密 3---返回\n");
gets(op);

if(strcmp(op,"1")==0 ||strcmp(op,"2")==0 )
{
printf("输入文本：");
gets(text);

for(i=0;text[i]!='\0';i++)
{
if((text[i]>='a'&&text[i]<='z') || (text[i]>='A'&&text[i]<='Z') )
{
if(strcmp(op,"1")==0)
{
p=text[i]>='a'? (text[i]-'a'):(text[i]-'A');
text[i]=text[i]+ alphabet[p]-(p+'A');
}
else
{
for(j=0;;j++)
if(alphabet[j]==text[i]||alphabet[j]==(text[i]-('a'-'A')))
break;
text[i]= text[i]>='a' ? (j+'a') :(j+'A');
}

}
}//for(i)

if(strcmp(op,"1")==0)
printf("加密后的文本为:" );
else
printf("解密后的文本为：");
printf("%s\n\n",text);

}
else if(strcmp(op,"3")==0)
{
printf("\n");
break;
}
else
{
printf("选择有误！请重新选择！\n");
}
}//while(1)
}

else if(strcmp(op,"2")==0)
{
exit(1);
}
else
{
printf("选择有误！请重新选择！\n");
}
}
return 0;
}

/*
输入样例
QWERTYUIOPASDFGHJKLZXCVBNM
Welcome to ZZSY2009!
输出样例
Vtsegdt zg MMLN2009!
*/

Answer 2

#include <iostream>

using namespace std;

int main()

{

char ch[100];

int i;

cout<<"请输入密文："<<endl;

cin>>ch;

for(i=0;(ch[i]!='\0')&&(i<100);i++)

{

if(((ch[i]>='d')&&(ch[i]<='z'))||

((ch[i]>='D')&&(ch[i]<='Z')))

{

ch[i]-=3;

}

else

{

switch(ch[i])

{

case 'a':ch[i]='x';break;

case 'A':ch[i]='X';break;

case 'b':ch[i]='y';break;

case 'B':ch[i]='Y';break;

case 'c':ch[i]='z';break;

case 'C':ch[i]='Z';break;

default:break;

}

}

}

cout<<"解密后："<<endl;

for(i=0;(ch[i]!='\0')&&(i<100);i++)

{

cout<<ch[i];

}

cout<<endl;

return 0;

}