Compilare: user.cpp: In function ‘int main()’: user.cpp:57:7: warning: unused variable ‘x11’ [-Wunused-variable] char x11[10],y11[10],x21[10],y21[10]; ^ user.cpp:57:15: warning: unused variable ‘y11’ [-Wunused-variable] char x11[10],y11[10],x21[10],y21[10]; ^ user.cpp:57:23: warning: unused variable ‘x21’ [-Wunused-variable] char x11[10],y11[10],x21[10],y21[10]; ^ user.cpp:57:31: warning: unused variable ‘y21’ [-Wunused-variable] char x11[10],y11[10],x21[10],y21[10]; ^ user.cpp:62:19: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%d",&t); ^ user.cpp:67:22: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f, "%d", &N); ^ user.cpp:70:44: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f, "%f%f%f%f", &x1, &y1, &x2, &y2); ^