Main.cc: In function 'int main()':
Main.cc:7:22: error: 'n2' was not declared in this scope
printf("%.3lf",-n2.5);
^
Main.cc:8:2: error: 'eise' was not declared in this scope
eise if(5<=n&&n<10)
^
Main.cc:10:7: error: expected ';' before 'if'
eise if(10<=n&&n<20)
^