/in/foo.c:1:1: error: unknown type name 'def'
    1 | def piecewise_function(x):
      | ^~~
/in/foo.c: In function 'piecewise_function':
/in/foo.c:1:26: error: expected declaration specifiers before ':' token
    1 | def piecewise_function(x):
      |                          ^
/in/foo.c:8:12: error: stray '#' in program
    8 |     else:  # x >= 25
      |            ^
/in/foo.c:1:5: warning: type of 'x' defaults to 'int' [-Wimplicit-int]
    1 | def piecewise_function(x):
      |     ^~~~~~~~~~~~~~~~~~
/in/foo.c:16: warning: control reaches end of non-void function [-Wreturn-type]