Compilare: user.cpp: In function ‘void read(int&, int&)’: user.cpp:19:19: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] a[strlen(a)-1]=NULL; ^ user.cpp:15:27: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%d%c",&n,&c); ^ user.cpp:17:22: warning: ignoring return value of ‘char* fgets(char*, int, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fgets(a,200005,f); ^ user.cpp:21:22: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%d",&m); ^ user.cpp:24:51: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%d%d%d",&b[i].c,&b[i].x,&b[i].y); ^