Main.cc: In function ‘long long int check(double)’: Main.cc:10:8: error: invalid types ‘int [1000007][double]’ for array subscript if(a[x]) return sum; ^ Main.cc:10:18: error: ‘sum’ was not declared in this scope if(a[x]) return sum; ^~~ Main.cc:15:5: error: invalid types ‘int [1000007][double]’ for array subscript a[x]=sum; ^