Main.cc: In function 'int main()': Main.cc:11:18: error: 'a' was not declared in this scope cin>>a[i][j]; ^ Main.cc:11:23: error: 'j' was not declared in this scope cin>>a[i][j]; ^ Main.cc:7:9: warning: unused variable 's' [-Wunused-variable] int s[6][6],n,m; ^