Language: C

char*c,b[];t,s;main(){read(0,b,c)for(c=strchr(b,10);*c++;t*=!!(*c-10))*c-49||(s=s<++t?t:s);printf("%d\n",s);exit(0);}

Compiler output:
main.c:1:12: warning: data definition has no type or storage class
    1 | char*c,b[];t,s;main(){read(0,b,c)for(c=strchr(b,10);*c++;t*=!!(*c-10))*c-49||(s=s<++t?t:s);printf("%d\n",s);exit(0);}
      |            ^
main.c:1:12: error: type defaults to 'int' in declaration of 't' [-Wimplicit-int]
main.c:1:14: error: type defaults to 'int' in declaration of 's' [-Wimplicit-int]
    1 | char*c,b[];t,s;main(){read(0,b,c)for(c=strchr(b,10);*c++;t*=!!(*c-10))*c-49||(s=s<++t?t:s);printf("%d\n",s);exit(0);}
      |              ^
main.c:1:16: error: return type defaults to 'int' [-Wimplicit-int]
    1 | char*c,b[];t,s;main(){read(0,b,c)for(c=strchr(b,10);*c++;t*=!!(*c-10))*c-49||(s=s<++t?t:s);printf("%d\n",s);exit(0);}
      |                ^~~~
main.c: In function 'main':
main.c:1:23: error: implicit declaration of function 'read' [-Wimplicit-function-declaration]
    1 | char*c,b[];t,s;main(){read(0,b,c)for(c=strchr(b,10);*c++;t*=!!(*c-10))*c-49||(s=s<++t?t:s);printf("%d\n",s);exit(0);}
      |                       ^~~~
main.c:1:34: error: expected ';' before 'for'
    1 | char*c,b[];t,s;main(){read(0,b,c)for(c=strchr(b,10);*c++;t*=!!(*c-10))*c-49||(s=s<++t?t:s);printf("%d\n",s);exit(0);}
      |                                  ^~~
      |                                  ;
main.c:1:92: error: implicit declaration of function 'printf' [-Wimplicit-function-declaration]
    1 | char*c,b[];t,s;main(){read(0,b,c)for(c=strchr(b,10);*c++;t*=!!(*c-10))*c-49||(s=s<++t?t:s);printf("%d\n",s);exit(0);}
      |                                                                                            ^~~~~~
main.c:1:1: note: include '<stdio.h>' or provide a declaration of 'printf'
  +++ |+#include <stdio.h>
    1 | char*c,b[];t,s;main(){read(0,b,c)for(c=strchr(b,10);*c++;t*=!!(*c-10))*c-49||(s=s<++t?t:s);printf("%d\n",s);exit(0);}
main.c:1:92: warning: incompatible implicit declaration of built-in function 'printf' [-Wbuiltin-declaration-mismatch]
    1 | char*c,b[];t,s;main(){read(0,b,c)for(c=strchr(b,10);*c++;t*=!!(*c-10))*c-49||(s=s<++t?t:s);printf("%d\n",s);exit(0);}
      |                                                                                            ^~~~~~
main.c:1:92: note: include '<stdio.h>' or provide a declaration of 'printf'
main.c:1:109: error: implicit declaration of function 'exit' [-Wimplicit-function-declaration]
    1 | char*c,b[];t,s;main(){read(0,b,c)for(c=strchr(b,10);*c++;t*=!!(*c-10))*c-49||(s=s<++t?t:s);printf("%d\n",s);exit(0);}
      |                                                                                                             ^~~~
main.c:1:1: note: include '<stdlib.h>' or provide a declaration of 'exit'
  +++ |+#include <stdlib.h>
    1 | char*c,b[];t,s;main(){read(0,b,c)for(c=strchr(b,10);*c++;t*=!!(*c-10))*c-49||(s=s<++t?t:s);printf("%d\n",s);exit(0);}
main.c:1:109: warning: incompatible implicit declaration of built-in function 'exit' [-Wbuiltin-declaration-mismatch]
    1 | char*c,b[];t,s;main(){read(0,b,c)for(c=strchr(b,10);*c++;t*=!!(*c-10))*c-49||(s=s<++t?t:s);printf("%d\n",s);exit(0);}
      |                                                                                                             ^~~~
main.c:1:109: note: include '<stdlib.h>' or provide a declaration of 'exit'
main.c: At top level:
main.c:1:8: warning: array 'b' assumed to have one element
    1 | char*c,b[];t,s;main(){read(0,b,c)for(c=strchr(b,10);*c++;t*=!!(*c-10))*c-49||(s=s<++t?t:s);printf("%d\n",s);exit(0);}
      |        ^