foo.cc: In function 'int main()':
foo.cc:5:19: warning: unused variable 'j' [-Wunused-variable]
    5 |  int a, b, t = 0, j, k, m, n;
      |                   ^
foo.cc:5:22: warning: unused variable 'k' [-Wunused-variable]
    5 |  int a, b, t = 0, j, k, m, n;
      |                      ^
foo.cc:6:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
    6 |  scanf("%d%d", &a, &b);
      |  ~~~~~^~~~~~~~~~~~~~~~

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