Compilare: user.cpp: In function ‘int main()’: user.cpp:25:6: warning: unused variable ‘i’ [-Wunused-variable] int i, M, comm = 0, len = 0; ^ user.cpp:25:9: warning: unused variable ‘M’ [-Wunused-variable] int i, M, comm = 0, len = 0; ^ user.cpp:26:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d\n", &N); ^ user.cpp:30:11: warning: ignoring return value of ‘char* fgets(char*, int, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] P[i] = i; ^