Compilare: main.cpp: In function 'int main()': main.cpp:18:12: warning: unused variable 'x' [-Wunused-variable] int a, n, x; ^ main.cpp:21:6: warning: unused variable 'dif' [-Wunused-variable] int dif = abs(a - n); ^~~ main.cpp:15:41: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("inversmodular.in", "r", stdin); ^ main.cpp:19:23: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &a, &n); ^