/in/foo.cc: In function 'int read()':
/in/foo.cc:13:9: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
         if(c=='-')f=-1;c=getchar();
         ^~
/in/foo.cc:13:24: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'if'
         if(c=='-')f=-1;c=getchar();
                        ^
/in/foo.cc: In function 'int main()':
/in/foo.cc:56:23: warning: variable 'key' set but not used [-Wunused-but-set-variable]
     int opt,a,b,k,x,y,key=0;
                       ^~~