Language: C

char s[258],p[258],f[];a,v,i,t,b;main(k){if(~scanf("%*d\n%[^\n]\n"+!k*4,s))for(a=0;++a<27;){for(memset(f,b=i=v=-1,26);++i<26;f[t]=i)v&=f[t=a*i%26];for(;!~v&&++b<26;p[i]=0,strstr(p,"that")|strstr(p,"this")&&main(!puts(p)))for(i=0;s[i];i++)p[i]=s[i]-32?(f[s[i]-97]+b)%26+97:32;}exit(0);}

Compiler output:
main.c:1:24: warning: data definition has no type or storage class
    1 | char s[258],p[258],f[];a,v,i,t,b;main(k){if(~scanf("%*d\n%[^\n]\n"+!k*4,s))for(a=0;++a<27;){for(memset(f,b=i=v=-1,26);++i<26;f[t]=i)v&=f[t=a*i%26];for(;!~v&&++b<26;p[i]=0,strstr(p,"that")|strstr(p,"this")&&main(!puts(p)))for(i=0;s[i];i++)p[i]=s[i]-32?(f[s[i]-97]+b)%26+97:32;}exit(0);}
      |                        ^
main.c:1:24: error: type defaults to 'int' in declaration of 'a' [-Wimplicit-int]
main.c:1:26: error: type defaults to 'int' in declaration of 'v' [-Wimplicit-int]
    1 | char s[258],p[258],f[];a,v,i,t,b;main(k){if(~scanf("%*d\n%[^\n]\n"+!k*4,s))for(a=0;++a<27;){for(memset(f,b=i=v=-1,26);++i<26;f[t]=i)v&=f[t=a*i%26];for(;!~v&&++b<26;p[i]=0,strstr(p,"that")|strstr(p,"this")&&main(!puts(p)))for(i=0;s[i];i++)p[i]=s[i]-32?(f[s[i]-97]+b)%26+97:32;}exit(0);}
      |                          ^
main.c:1:28: error: type defaults to 'int' in declaration of 'i' [-Wimplicit-int]
    1 | char s[258],p[258],f[];a,v,i,t,b;main(k){if(~scanf("%*d\n%[^\n]\n"+!k*4,s))for(a=0;++a<27;){for(memset(f,b=i=v=-1,26);++i<26;f[t]=i)v&=f[t=a*i%26];for(;!~v&&++b<26;p[i]=0,strstr(p,"that")|strstr(p,"this")&&main(!puts(p)))for(i=0;s[i];i++)p[i]=s[i]-32?(f[s[i]-97]+b)%26+97:32;}exit(0);}
      |                            ^
main.c:1:30: error: type defaults to 'int' in declaration of 't' [-Wimplicit-int]
    1 | char s[258],p[258],f[];a,v,i,t,b;main(k){if(~scanf("%*d\n%[^\n]\n"+!k*4,s))for(a=0;++a<27;){for(memset(f,b=i=v=-1,26);++i<26;f[t]=i)v&=f[t=a*i%26];for(;!~v&&++b<26;p[i]=0,strstr(p,"that")|strstr(p,"this")&&main(!puts(p)))for(i=0;s[i];i++)p[i]=s[i]-32?(f[s[i]-97]+b)%26+97:32;}exit(0);}
      |                              ^
main.c:1:32: error: type defaults to 'int' in declaration of 'b' [-Wimplicit-int]
    1 | char s[258],p[258],f[];a,v,i,t,b;main(k){if(~scanf("%*d\n%[^\n]\n"+!k*4,s))for(a=0;++a<27;){for(memset(f,b=i=v=-1,26);++i<26;f[t]=i)v&=f[t=a*i%26];for(;!~v&&++b<26;p[i]=0,strstr(p,"that")|strstr(p,"this")&&main(!puts(p)))for(i=0;s[i];i++)p[i]=s[i]-32?(f[s[i]-97]+b)%26+97:32;}exit(0);}
      |                                ^
main.c:1:34: error: return type defaults to 'int' [-Wimplicit-int]
    1 | char s[258],p[258],f[];a,v,i,t,b;main(k){if(~scanf("%*d\n%[^\n]\n"+!k*4,s))for(a=0;++a<27;){for(memset(f,b=i=v=-1,26);++i<26;f[t]=i)v&=f[t=a*i%26];for(;!~v&&++b<26;p[i]=0,strstr(p,"that")|strstr(p,"this")&&main(!puts(p)))for(i=0;s[i];i++)p[i]=s[i]-32?(f[s[i]-97]+b)%26+97:32;}exit(0);}
      |                                  ^~~~
main.c: In function 'main':
main.c:1:34: error: type of 'k' defaults to 'int' [-Wimplicit-int]
main.c:1:46: error: implicit declaration of function 'scanf' [-Wimplicit-function-declaration]
    1 | char s[258],p[258],f[];a,v,i,t,b;main(k){if(~scanf("%*d\n%[^\n]\n"+!k*4,s))for(a=0;++a<27;){for(memset(f,b=i=v=-1,26);++i<26;f[t]=i)v&=f[t=a*i%26];for(;!~v&&++b<26;p[i]=0,strstr(p,"that")|strstr(p,"this")&&main(!puts(p)))for(i=0;s[i];i++)p[i]=s[i]-32?(f[s[i]-97]+b)%26+97:32;}exit(0);}
      |                                              ^~~~~
main.c:1:1: note: include '<stdio.h>' or provide a declaration of 'scanf'
  +++ |+#include <stdio.h>
    1 | char s[258],p[258],f[];a,v,i,t,b;main(k){if(~scanf("%*d\n%[^\n]\n"+!k*4,s))for(a=0;++a<27;){for(memset(f,b=i=v=-1,26);++i<26;f[t]=i)v&=f[t=a*i%26];for(;!~v&&++b<26;p[i]=0,strstr(p,"that")|strstr(p,"this")&&main(!puts(p)))for(i=0;s[i];i++)p[i]=s[i]-32?(f[s[i]-97]+b)%26+97:32;}exit(0);}
main.c:1:46: warning: incompatible implicit declaration of built-in function 'scanf' [-Wbuiltin-declaration-mismatch]
    1 | char s[258],p[258],f[];a,v,i,t,b;main(k){if(~scanf("%*d\n%[^\n]\n"+!k*4,s))for(a=0;++a<27;){for(memset(f,b=i=v=-1,26);++i<26;f[t]=i)v&=f[t=a*i%26];for(;!~v&&++b<26;p[i]=0,strstr(p,"that")|strstr(p,"this")&&main(!puts(p)))for(i=0;s[i];i++)p[i]=s[i]-32?(f[s[i]-97]+b)%26+97:32;}exit(0);}
      |                                              ^~~~~
main.c:1:46: note: include '<stdio.h>' or provide a declaration of 'scanf'
main.c:1:97: error: implicit declaration of function 'memset' [-Wimplicit-function-declaration]
    1 | char s[258],p[258],f[];a,v,i,t,b;main(k){if(~scanf("%*d\n%[^\n]\n"+!k*4,s))for(a=0;++a<27;){for(memset(f,b=i=v=-1,26);++i<26;f[t]=i)v&=f[t=a*i%26];for(;!~v&&++b<26;p[i]=0,strstr(p,"that")|strstr(p,"this")&&main(!puts(p)))for(i=0;s[i];i++)p[i]=s[i]-32?(f[s[i]-97]+b)%26+97:32;}exit(0);}
      |                                                                                                 ^~~~~~
main.c:1:1: note: include '<string.h>' or provide a declaration of 'memset'
  +++ |+#include <string.h>
    1 | char s[258],p[258],f[];a,v,i,t,b;main(k){if(~scanf("%*d\n%[^\n]\n"+!k*4,s))for(a=0;++a<27;){for(memset(f,b=i=v=-1,26);++i<26;f[t]=i)v&=f[t=a*i%26];for(;!~v&&++b<26;p[i]=0,strstr(p,"that")|strstr(p,"this")&&main(!puts(p)))for(i=0;s[i];i++)p[i]=s[i]-32?(f[s[i]-97]+b)%26+97:32;}exit(0);}
main.c:1:97: warning: incompatible implicit declaration of built-in function 'memset' [-Wbuiltin-declaration-mismatch]
    1 | char s[258],p[258],f[];a,v,i,t,b;main(k){if(~scanf("%*d\n%[^\n]\n"+!k*4,s))for(a=0;++a<27;){for(memset(f,b=i=v=-1,26);++i<26;f[t]=i)v&=f[t=a*i%26];for(;!~v&&++b<26;p[i]=0,strstr(p,"that")|strstr(p,"this")&&main(!puts(p)))for(i=0;s[i];i++)p[i]=s[i]-32?(f[s[i]-97]+b)%26+97:32;}exit(0);}
      |                                                                                                 ^~~~~~
main.c:1:97: note: include '<string.h>' or provide a declaration of 'memset'
main.c:1:172: error: implicit declaration of function 'strstr' [-Wimplicit-function-declaration]
    1 | char s[258],p[258],f[];a,v,i,t,b;main(k){if(~scanf("%*d\n%[^\n]\n"+!k*4,s))for(a=0;++a<27;){for(memset(f,b=i=v=-1,26);++i<26;f[t]=i)v&=f[t=a*i%26];for(;!~v&&++b<26;p[i]=0,strstr(p,"that")|strstr(p,"this")&&main(!puts(p)))for(i=0;s[i];i++)p[i]=s[i]-32?(f[s[i]-97]+b)%26+97:32;}exit(0);}
      |                                                                                                                                                                            ^~~~~~
main.c:1:172: note: include '<string.h>' or provide a declaration of 'strstr'
main.c:1:172: warning: incompatible implicit declaration of built-in function 'strstr' [-Wbuiltin-declaration-mismatch]
main.c:1:172: note: include '<string.h>' or provide a declaration of 'strstr'
main.c:1:188: error: invalid operands to binary | (have 'char *' and 'char *')
    1 | char s[258],p[258],f[];a,v,i,t,b;main(k){if(~scanf("%*d\n%[^\n]\n"+!k*4,s))for(a=0;++a<27;){for(memset(f,b=i=v=-1,26);++i<26;f[t]=i)v&=f[t=a*i%26];for(;!~v&&++b<26;p[i]=0,strstr(p,"that")|strstr(p,"this")&&main(!puts(p)))for(i=0;s[i];i++)p[i]=s[i]-32?(f[s[i]-97]+b)%26+97:32;}exit(0);}
      |                                                                                                                                                                            ~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~
      |                                                                                                                                                                            |                |
      |                                                                                                                                                                            char *           char *
main.c:1:213: error: implicit declaration of function 'puts' [-Wimplicit-function-declaration]
    1 | char s[258],p[258],f[];a,v,i,t,b;main(k){if(~scanf("%*d\n%[^\n]\n"+!k*4,s))for(a=0;++a<27;){for(memset(f,b=i=v=-1,26);++i<26;f[t]=i)v&=f[t=a*i%26];for(;!~v&&++b<26;p[i]=0,strstr(p,"that")|strstr(p,"this")&&main(!puts(p)))for(i=0;s[i];i++)p[i]=s[i]-32?(f[s[i]-97]+b)%26+97:32;}exit(0);}
      |                                                                                                                                                                                                                     ^~~~
main.c:1:213: note: include '<stdio.h>' or provide a declaration of 'puts'
main.c:1:277: error: implicit declaration of function 'exit' [-Wimplicit-function-declaration]
    1 | char s[258],p[258],f[];a,v,i,t,b;main(k){if(~scanf("%*d\n%[^\n]\n"+!k*4,s))for(a=0;++a<27;){for(memset(f,b=i=v=-1,26);++i<26;f[t]=i)v&=f[t=a*i%26];for(;!~v&&++b<26;p[i]=0,strstr(p,"that")|strstr(p,"this")&&main(!puts(p)))for(i=0;s[i];i++)p[i]=s[i]-32?(f[s[i]-97]+b)%26+97:32;}exit(0);}
      |                                                                                                                                                                                                                                                                                     ^~~~
main.c:1:1: note: include '<stdlib.h>' or provide a declaration of 'exit'
  +++ |+#include <stdlib.h>
    1 | char s[258],p[258],f[];a,v,i,t,b;main(k){if(~scanf("%*d\n%[^\n]\n"+!k*4,s))for(a=0;++a<27;){for(memset(f,b=i=v=-1,26);++i<26;f[t]=i)v&=f[t=a*i%26];for(;!~v&&++b<26;p[i]=0,strstr(p,"that")|strstr(p,"this")&&main(!puts(p)))for(i=0;s[i];i++)p[i]=s[i]-32?(f[s[i]-97]+b)%26+97:32;}exit(0);}
main.c:1:277: warning: incompatible implicit declaration of built-in function 'exit' [-Wbuiltin-declaration-mismatch]
    1 | char s[258],p[258],f[];a,v,i,t,b;main(k){if(~scanf("%*d\n%[^\n]\n"+!k*4,s))for(a=0;++a<27;){for(memset(f,b=i=v=-1,26);++i<26;f[t]=i)v&=f[t=a*i%26];for(;!~v&&++b<26;p[i]=0,strstr(p,"that")|strstr(p,"this")&&main(!puts(p)))for(i=0;s[i];i++)p[i]=s[i]-32?(f[s[i]-97]+b)%26+97:32;}exit(0);}
      |                                                                                                                                                                                                                                                                                     ^~~~
main.c:1:277: note: include '<stdlib.h>' or provide a declaration of 'exit'
main.c: At top level:
main.c:1:20: warning: array 'f' assumed to have one element
    1 | char s[258],p[258],f[];a,v,i,t,b;main(k){if(~scanf("%*d\n%[^\n]\n"+!k*4,s))for(a=0;++a<27;){for(memset(f,b=i=v=-1,26);++i<26;f[t]=i)v&=f[t=a*i%26];for(;!~v&&++b<26;p[i]=0,strstr(p,"that")|strstr(p,"this")&&main(!puts(p)))for(i=0;s[i];i++)p[i]=s[i]-