Main.cc: In function 'int main()': Main.cc:14:14: error: redeclaration of 'int a2' int a,a1,a2,a2; ^ Main.cc:14:11: error: 'int a2' previously declared here int a,a1,a2,a2; ^ Main.cc:18:2: error: 'a3' was not declared in this scope a3=a/100%10; ^