compiler: duplicatedly declared variable 'x' in line 3
compiler: undeclared variable 'y' in line 5
compiler: undeclared variable 'y' in line 6
compiler: undeclared variable 'y' in line 7
compiler: illegal syntax "WRITESP;" in line 8
compiler: illegal syntax "WRITELN" in line 10
compiler: illegal syntax "the program ends here" in line 12