Compilare: user.cpp: In function ‘int main(int, char**)’: user.cpp:15:26: warning: format ‘%d’ expects argument of type ‘int’, but argument 3 has type ‘long int’ [-Wformat=] fprintf(g, "%d\n", a + b); ^ user.cpp:13:22: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f, "%ld", &a); ^ user.cpp:14:22: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f, "%ld", &b); ^