# include<Stdio.h>
# include<String.h>

int main()
{
    int result=1;
    int i;
    int count=o
    char Text[128]={'10'};
    char cryptograph[128]={'10'}
    while(1)
    {
        if(result==1)
        {
            Printf("请输入需要加密的明文;\n");
            scanf("%s",&Text);
            count=strlen(Text);
            for(i=0;i<count;i++)
            {
               cryptograph[i]=Text[i]+i+5;
            }
         cryptograph[i]='\0';
         /*输出密文信息*/
            Printf("加密后的密文是:%s\n",cryptograph);
        }
            else if(result==2)
            {
               Count=Strlen(Text);
               for(i=0;i<count;i++)
                {
                   Text[i]=Cryptograph[i]-i-5;
                }
               Text[i]='\0';
               /*输出明文信息*/
                   Printf("解密后的明文是:%s\n",Text);
            }
            else if(result==3)
            {
               break
            }
            else
            {
               printf("请输入命令符;\n");
            }
 
           /*输出字符串*/
           Printf("输入1加密新的明文,输入2对刚加密的密文进行解密,输入3退出系统;\n");
           Printf("请输入命令符;\n");
           Scanf("%d",&result);
    }

       Resturn 0;
}

不好意思。走错房了