Main.cc: In function ‘int main()’:
Main.cc:5:2: error: ‘cin’ was not declared in this scope
cin>>a;
^~~
Main.cc:5:2: note: suggested alternative:
In file included from Main.cc:1:0:
/usr/include/c++/7/iostream:60:18: note: ‘std::cin’
extern istream cin; /// Linked to standard input
^~~
Main.cc:7:7: error: ‘i’ was not declared in this scope
b=1/i+b;
^
Main.cc:12:16: error: ‘i’ was not declared in this scope
printf("%.0f",i);
^