foo.cc: In function 'void dts::main()':
foo.cc:20:9: error: 'cin' was not declared in this scope
         cin<<n<<endl;
         ^~~
foo.cc:20:9: note: suggested alternative: 'sin'
         cin<<n<<endl;
         ^~~
         sin
foo.cc:20:17: error: 'endl' was not declared in this scope
         cin<<n<<endl;
                 ^~~~
foo.cc:20:17: note: suggested alternative: 'ynl'
         cin<<n<<endl;
                 ^~~~
                 ynl
foo.cc:23:9: error: 'cout' was not declared in this scope
         cout<<n<<endl;
         ^~~~
foo.cc:23:9: note: suggested alternative: 'cosl'
         cout<<n<<endl;
         ^~~~
         cosl
foo.cc:22:27: warning: unused variable 'b' [-Wunused-variable]
         int a=random(n+1),b=n-a;
                           ^

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