foo.cc: In function 'int main()':
foo.cc:7:9: error: 'scanf_s' was not declared in this scope; did you mean 'scanf'?
    7 |         scanf_s("%d%d%d", &a, &m, &k);
      |         ^~~~~~~
      |         scanf
foo.cc:5:30: warning: unused variable 'y' [-Wunused-variable]
    5 |         float a, m, k, g, x, y, z;//a是西瓜重量，m是赠送电量，k是单价
      |                              ^
foo.cc:5:33: warning: unused variable 'z' [-Wunused-variable]
    5 |         float a, m, k, g, x, y, z;//a是西瓜重量，m是赠送电量，k是单价
      |                                 ^

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