1006 Do the Untwist, 1006 dotheuntwist

1006 Do the Untwist, 1006 dotheuntwist

Evaluate the knowledge of programming and convert characters and numbers. The format is to describe the conversion rules of plain text and dark text.

 1 #include <stdio.h> 2 #include <string.h> 3  4 #define MAXLEN 71 5  6 int length; 7  8 void toCode(int code[],char text[]){ 9     int i;10     for(i=0;i<length;i++){11         if(text[i] == '_')12             code[i] = 0;13         else if(text[i] == '.')14                 code[i] = 27;15             else16                 code[i] = text[i] - 96;17     }18 }19 20 void toText(char text[],int code[]){21     int i;22     for(i=0;i<length;i++){23         if(code[i] == 0)24             text[i] = '_';25         else if(code[i] == 27)26                 text[i] = '.';27             else28                 text[i] = code[i] + 96;29     }30     text[i] = 0;31 }32 33 int inRange(int n){34     if(n>=0&&n<=27)35         return 1;36     return 0;37 }38 39 void untwist(char textC[],int k){40     int i,j;41     int codeC[MAXLEN],codeP[MAXLEN];42     char textP[MAXLEN];43 44     toCode(codeC,textC);45     for(i=0;i<length;i++){46         j = (k*i)%length;47         if(inRange(codeC[i] + i)) 48             codeP[j] = codeC[i] + i;49         else if(inRange(codeC[i] + i - 28)) 50                 codeP[j] = codeC[i] + i - 28;51             else if(inRange(codeC[i] + i - 56)) 52                     codeP[j] = codeC[i] + i - 56;53                 else if(inRange(codeC[i] + i - 84)) 54                         codeP[j] = codeC[i] + i - 84;55     }56     toText(textP,codeP);57     printf("%s\n",textP);58 }59 60 int main(){61     int k;62     char textC[MAXLEN];63     while(scanf("%d",&k)&&k){64         scanf("%s",textC);65         length = strlen(textC);66         untwist(textC,k);67     }68     return 0;69 }

 

C language programmers, please help solve problems

It is a simple encryption and decryption method, similar to the replacement method, but it is not directly replaced.
But I don't know that the super sb has to be written in the bird text. Some words seem to be wrong.