Main.cc:7:6: error: expected initializer before ‘a’ node a[1010]; ^ Main.cc: In function ‘int main()’: Main.cc:20:21: error: ‘a’ was not declared in this scope scanf("%d",&a[i].t); ^ Main.cc:23:10: error: ‘a’ was not declared in this scope sort(a,a+n,cmp); ^ Main.cc:18:10: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&n); ~~~~~^~~~~~~~~