Main.cc: In function ‘int main()’: Main.cc:12:11: error: ‘n2’ was not declared in this scope int n1=0;n2=1,d; ^~ Main.cc:12:11: note: suggested alternative: ‘n1’ int n1=0;n2=1,d; ^~ n1 Main.cc:12:16: error: ‘d’ was not declared in this scope int n1=0;n2=1,d; ^ Main.cc:25:4: error: ‘gcd’ was not declared in this scope d=gcd(n1,n2); ^~~ Main.cc:25:4: note: suggested alternative: ‘gcvt’ d=gcd(n1,n2); ^~~ gcvt Main.cc:13:7: warning: unused variable ‘s’ [-Wunused-variable] char s[20]; ^