Main.cc: In function 'int main()': Main.cc:8:15: error: redeclaration of 'int a' int a,b,c,a; ^ Main.cc:8:9: note: 'int a' previously declared here int a,b,c,a; ^ Main.cc:9:10: error: 'x' was not declared in this scope cin>>x>>y>>z; ^ Main.cc:9:13: error: 'y' was not declared in this scope cin>>x>>y>>z; ^ Main.cc:9:16: error: 'z' was not declared in this scope cin>>x>>y>>z; ^