Compilare: user.cpp: In function ‘int main()’: user.cpp:10:22: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f1, "%d", &T); ^ user.cpp:17:23: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f1, "%s", nr); ^ user.cpp:42:33: warning: ‘ultima_cifra’ may be used uninitialized in this function [-Wmaybe-uninitialized] ultima_cifra = (ultima_cifra + 7*a)%10; ^