Main.cc: In function ‘int main()’: Main.cc:13:12: error: invalid types ‘int[int]’ for array subscript if (a[c2]*2+1>a[c3]*3+1) ^ Main.cc:13:22: error: invalid types ‘int[int]’ for array subscript if (a[c2]*2+1>a[c3]*3+1) ^ Main.cc:9:17: warning: unused variable ‘cur’ [-Wunused-variable] int c2=1,c3=1,cur=1; ^~~