port_facility.cpp:44:6: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
main() {
^
port_facility.cpp: In function 'int main()':
port_facility.cpp:46:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
scanf("%d", &n);
~~~~~^~~~~~~~~~
port_facility.cpp:48:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
scanf("%d %d", &ar[i].fr, &ar[i].sc);
~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~