Compilare: user.cpp: In function ‘void build(int, int, int)’: user.cpp:14:43: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf (fin,"%d%d%d\n",&nr,&j,&j2); ^ user.cpp: In function ‘void update(int, int, int, int)’: user.cpp:40:43: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf (fin,"%d%d%d\n",&nr,&j,&j2); ^ user.cpp: In function ‘int main()’: user.cpp:93:40: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf (fin,"%d%d%d%d",&n,&k,&x,&y); ^ user.cpp:98:35: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf (fin,"%d\n",&i); ^ user.cpp:102:54: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf (fin,"%d%d%d%d\n",&ii,&x2,&jj,&y2); ^