foo.cc:2:1: error: '::main' must return 'int'
    2 | void main()
      | ^~~~
foo.cc: In function 'int main()':
foo.cc:10:25: error: 'a' was not declared in this scope
   10 |     outcome=outcome*10+(a%10);
      |                         ^
foo.cc:6:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
    6 |     scanf("%d",&x);
      |     ~~~~~^~~~~~~~~

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