/in/foo.c: In function 'main':
/in/foo.c:4:2: warning: implicit declaration of function 'scanf' [-Wimplicit-function-declaration]
  scanf("%d%d%d",&a,&b,&c);
  ^~~~~
/in/foo.c:4:2: warning: incompatible implicit declaration of built-in function 'scanf'
/in/foo.c:4:2: note: include '<stdio.h>' or provide a declaration of 'scanf'
/in/foo.c:6:3: warning: implicit declaration of function 'printf' [-Wimplicit-function-declaration]
   printf("%d",c+(b-1)*31);
   ^~~~~~
/in/foo.c:6:3: warning: incompatible implicit declaration of built-in function 'printf'
/in/foo.c:6:3: note: include '<stdio.h>' or provide a declaration of 'printf'
/in/foo.c:11:6: warning: incompatible implicit declaration of built-in function 'printf'
      printf("%d",(b-1)*30-2+(b-1)/2+c);
      ^~~~~~
/in/foo.c:11:6: note: include '<stdio.h>' or provide a declaration of 'printf'
/in/foo.c:13:6: warning: incompatible implicit declaration of built-in function 'printf'
      printf("%d",(b-1)*30-2+(b-1)/2+c+1);
      ^~~~~~
/in/foo.c:13:6: note: include '<stdio.h>' or provide a declaration of 'printf'
/in/foo.c:16:6: warning: incompatible implicit declaration of built-in function 'printf'
      printf("%d",(b-1)*30-2+(b+1)/2+c);
      ^~~~~~
/in/foo.c:16:6: note: include '<stdio.h>' or provide a declaration of 'printf'
/in/foo.c:18:6: warning: incompatible implicit declaration of built-in function 'printf'
      printf("%d",(b-1)*30-2+(b+1)/2+c+1);
      ^~~~~~
/in/foo.c:18:6: note: include '<stdio.h>' or provide a declaration of 'printf'
/in/foo.c:8:5: warning: suggest explicit braces to avoid ambiguous 'else' [-Wparentheses]
   if(b<9)
     ^
/in/foo.c:7:2: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
  if(b>2)
  ^~
/in/foo.c:19:3: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'if'
   if(b>8&&b<13)
   ^~
/in/foo.c:22:6: warning: incompatible implicit declaration of built-in function 'printf'
      printf("%d",(b-1)*30-2+(b+1)/2+c);
      ^~~~~~
/in/foo.c:22:6: note: include '<stdio.h>' or provide a declaration of 'printf'
/in/foo.c:24:6: warning: incompatible implicit declaration of built-in function 'printf'
      printf("%d",(b-1)*30-2+(b+1)/2+c+1);
      ^~~~~~
/in/foo.c:24:6: note: include '<stdio.h>' or provide a declaration of 'printf'
/in/foo.c:27:6: warning: incompatible implicit declaration of built-in function 'printf'
      printf("%d",(b-1)*30-2+b/2+c);
      ^~~~~~
/in/foo.c:27:6: note: include '<stdio.h>' or provide a declaration of 'printf'
/in/foo.c:29:6: warning: incompatible implicit declaration of built-in function 'printf'
      printf("%d",(b-1)*30-2+b/2+c+1);
      ^~~~~~
/in/foo.c:29:6: note: include '<stdio.h>' or provide a declaration of 'printf'
/in/foo.c:19:5: warning: suggest explicit braces to avoid ambiguous 'else' [-Wparentheses]
   if(b>8&&b<13)
     ^