foo.cpp: In function 'long long int abs1(long long int)':
foo.cpp:9:53: error: expected primary-expression before '?' token
 inline long long abs1(long long num) {  return num>=?num:-num; }
                                                     ^
foo.cpp:9:64: warning: control reaches end of non-void function [-Wreturn-type]
 inline long long abs1(long long num) {  return num>=?num:-num; }
                                                                ^