foo.cc: In function 'int main()':
foo.cc:6:34: warning: format '%d' expects argument of type 'int*', but argument 2 has type 'long long int*' [-Wformat=]
  scanf("%d%d%d%d", &a, &b, &c, &d);
                    ~~            ^
foo.cc:6:34: warning: format '%d' expects argument of type 'int*', but argument 3 has type 'long long int*' [-Wformat=]
foo.cc:6:34: warning: format '%d' expects argument of type 'int*', but argument 4 has type 'long long int*' [-Wformat=]
foo.cc:6:34: warning: format '%d' expects argument of type 'int*', but argument 5 has type 'long long int*' [-Wformat=]
foo.cc:7:28: warning: format '%ld' expects argument of type 'long int', but argument 2 has type 'long long int' [-Wformat=]
     printf("%ld", a*d - b*c);
                   ~~~~~~~~~^
foo.cc:6:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d%d%d%d", &a, &b, &c, &d);
  ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~

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