Compilare: user.cpp: In function ‘int main()’: user.cpp:16:15: warning: unused variable ‘i’ [-Wunused-variable] int n, m, i, j; ^ user.cpp:16:18: warning: unused variable ‘j’ [-Wunused-variable] int n, m, i, j; ^ user.cpp:20:30: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fi,"%d%d", &n, &m); ^ user.cpp:24:32: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fi,"%d", &x); ^