foo.cpp: In function 'int main()':
foo.cpp:7:7: warning: unused variable 'k' [-Wunused-variable]
  char k,d[100];
       ^
foo.cpp:8:14: warning: unused variable 'aa' [-Wunused-variable]
  int a=0,b=0,aa=0,bb=0,i=0;
              ^~
foo.cpp:8:19: warning: unused variable 'bb' [-Wunused-variable]
  int a=0,b=0,aa=0,bb=0,i=0;
                   ^~
foo.cpp:9:15: warning: 'd[-1]' is used uninitialized in this function [-Wuninitialized]
  for(i=0;d[i-1]!='E';i++)
          ~~~~~^