foo.c: In function 'main':
foo.c:5:5: error: 'cin' undeclared (first use in this function)
    5 |     cin>>a>>b>>c;
      |     ^~~
foo.c:5:5: note: each undeclared identifier is reported only once for each function it appears in
foo.c:6:5: error: expected declaration or statement at end of input
    6 |     printf("hello, world\n");
      |     ^~~~~~

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