Main.cc: In function 'int main()':
Main.cc:7:2: error: 'F' was not declared in this scope
F =c*9/5+32;
^
Main.cc:4:10: warning: unused variable 'f' [-Wunused-variable]
double f,c;
^
Main.cc:5:6: warning: unused variable 'a' [-Wunused-variable]
char a;
^