foo.cc: In function 'int main()':
foo.cc:14:19: warning: format '%ld' expects argument of type 'long int', but argument 2 has type 'long long int' [-Wformat=]
   printf("%ld\n",b);
                   ^
foo.cc:26:20: warning: format '%ld' expects argument of type 'long int', but argument 2 has type 'long long int' [-Wformat=]
   printf("-%ld\n",b);
                    ^
foo.cc:23:9: warning: 'b' may be used uninitialized in this function [-Wmaybe-uninitialized]
    b = b*10+a%10;
        ~^~~

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