Compilare: user.cpp: In function ‘void back()’: user.cpp:18:15: warning: unused variable ‘aux’ [-Wunused-variable] int i, j, aux, chg; ^ user.cpp:18:20: warning: unused variable ‘chg’ [-Wunused-variable] int i, j, aux, chg; ^ user.cpp: In function ‘int main()’: user.cpp:77:12: warning: unused variable ‘j’ [-Wunused-variable] int i, j; ^ user.cpp:76:38: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin, "%d%d%d", &N, &M, &I); ^ user.cpp:80:36: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin, "%d%d", &l, &c); ^