[结题报告]458 - The Decoder Time limit: 3.000 seconds-优快云博客

本文介绍了一个简单的程序，该程序可以解码特定ASCII字符集编码的消息。通过将每个字符的ASCII值减去7来实现解码，从而还原原始消息。

The Decoder

Write a complete program that will correctly decode a set of characters into a valid message. Your program should read a given file of a simple coded set of characters and print the exact message that the characters contain. The code key for this simple coding is a one for one character substitution based upon a single arithmetic manipulation of the printable portion of the ASCII character set.

Input and Output

For example: with the input file that contains:

1JKJ'pz'{ol'{yhklthyr'vm'{ol'Jvu{yvs'Kh{h'Jvywvyh{pvu5
1PIT'pz'h'{yhklthyr'vm'{ol'Pu{lyuh{pvuhs'I|zpulzz'Thjopul'Jvywvyh{pvu5
1KLJ'pz'{ol'{yhklthyr'vm'{ol'Kpnp{hs'Lx|pwtlu{'Jvywvyh{pvu5

your program should print the message:

*CDC is the trademark of the Control Data Corporation.
*IBM is a trademark of the International Business Machine Corporation.
*DEC is the trademark of the Digital Equipment Corporation.

Your program should accept all sets of characters that use the same encoding scheme and should print the actual message of each set of characters.

Sample Input

1JKJ'pz'{ol'{yhklthyr'vm'{ol'Jvu{yvs'Kh{h'Jvywvyh{pvu5
1PIT'pz'h'{yhklthyr'vm'{ol'Pu{lyuh{pvuhs'I|zpulzz'Thjopul'Jvywvyh{pvu5
1KLJ'pz'{ol'{yhklthyr'vm'{ol'Kpnp{hs'Lx|pwtlu{'Jvywvyh{pvu5

Sample Output

*CDC is the trademark of the Control Data Corporation.
*IBM is a trademark of the International Business Machine Corporation.
*DEC is the trademark of the Digital Equipment Corporation.


代码参考:
本题主要是将字符串的每个部分都进行变化，通过观察可是原码和变化码之间ASCII码相差7.

#include"stdio.h"
void fun(char *p)    //自定义函数;  
 {  int i=0;         //定义变量i,控制循环; 
     while(p[i])      //循环解码; 
    {p[i]-=7;            
     i++;}
    p[i]='\0';          //字符串结束; 
     } 
main()
 {    char s[30000];         //申请数组 ; 
       while(gets(s))           
         { fun(s);               //调用函数; 
           printf("%s\n",s);        //输出; 
         } 
       }