Main.cc: In function ‘int main()’: Main.cc:7:42: error: ‘by’ was not declared in this scope cout << fixed << setprecision(2) << (by-ax)/(b-a); ^~ Main.cc:7:42: note: suggested alternative: ‘y’ cout << fixed << setprecision(2) << (by-ax)/(b-a); ^~ y Main.cc:7:45: error: ‘ax’ was not declared in this scope cout << fixed << setprecision(2) << (by-ax)/(b-a); ^~ Main.cc:7:45: note: suggested alternative: ‘x’ cout << fixed << setprecision(2) << (by-ax)/(b-a); ^~ x