Compilare: user.cpp: In function ‘void back(int)’: user.cpp:25:39: warning: format ‘%d’ expects argument of type ‘int’, but argument 3 has type ‘std::pair<int, int>’ [-Wformat=] fprintf(g,"%d %d ",*it,*it); ^ user.cpp:25:39: warning: format ‘%d’ expects argument of type ‘int’, but argument 4 has type ‘std::pair<int, int>’ [-Wformat=] user.cpp:27:40: warning: format ‘%d’ expects argument of type ‘int’, but argument 3 has type ‘std::pair<int, int>’ [-Wformat=] fprintf(g,"%d %d\n",*it,*it); ^ user.cpp:27:40: warning: format ‘%d’ expects argument of type ‘int’, but argument 4 has type ‘std::pair<int, int>’ [-Wformat=] user.cpp: In function ‘int main()’: user.cpp:186:34: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%d %d %d",&N,&M,&I); ^ user.cpp:191:32: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%d %d",&x,&y); ^