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{pvu51PIT'pz'h'{yhklthyr'vm'{ol'Pu{lyuh{pvuhs'I|zpulzz'Thjopul'Jvywvyh{pvu51KLJ'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{pvu51PIT'pz'h'{yhklthyr'vm'{ol'Pu{lyuh{pvuhs'I|zpulzz'Thjopul'Jvywvyh{pvu51KLJ'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;          }        }