foo.cc: In function 'int main()':
foo.cc:7:12: error: expected '(' before 'a'
     while  a>1
            ^
foo.cc:8:7: error: expected ')' before 'if'
       if a%2=1;a=3*a+1;
       ^~
foo.cc:8:10: error: expected '(' before 'a'
       if a%2=1;a=3*a+1;
          ^
foo.cc:10:7: error: expected ';' before 'else'
       else  a=a/2;
       ^~~~
foo.cc:12:5: error: expected ';' before 'cout'
     cout << b<< endl;
     ^~~~

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