/in/foo.c: In function 'main':
/in/foo.c:7:2: warning: implicit declaration of function 'scanf' [-Wimplicit-function-declaration]
  scanf("%[^\n]",s);
  ^~~~~
/in/foo.c:7:2: warning: incompatible implicit declaration of built-in function 'scanf'
/in/foo.c:7:2: note: include '<stdio.h>' or provide a declaration of 'scanf'
/in/foo.c:12:3: warning: implicit declaration of function 'printf' [-Wimplicit-function-declaration]
   printf("%c",s[i]);
   ^~~~~~
/in/foo.c:12:3: warning: incompatible implicit declaration of built-in function 'printf'
/in/foo.c:12:3: note: include '<stdio.h>' or provide a declaration of 'printf'
/in/foo.c: In function 'mystrlen':
/in/foo.c:36:2: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
  for(int i=0;s[i]!=0;i++)
  ^~~
/in/foo.c:38:3: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'for'
   return count;
   ^~~~~~