foo.cpp: In function 'bool sou(long int)':
foo.cpp:9:11: warning: unused variable 'i' [-Wunused-variable]
      long i;
           ^
foo.cpp: In function 'int main()':
foo.cpp:43:7: error: 'd' was not declared in this scope
       d=0;               
       ^
foo.cpp:56:7: error: 'd' was not declared in this scope
       d=0;               
       ^