3000. ROT13加密和解密

    char str[1005];int count=0;
    gets(str);
    count=strlen(str);
    for(j=0;j<count;j++)
    {
        if((str[j]<='m'&&str[j]>='a')||(str[j]<='M'&&str[j]>='A'))
            str[j]=str[j]+13;
        else if((str[j]>='n'&&str[j]<='z')||(str[j]>='N'&&str[j]<='Z'))
            str[j]=str[j]-13;
    }
    printf("case #%d:\n",i);
    for(j=0;j<count;j++)
        printf("%c",str[j]);
    printf("\n");
}