Compilare: user.cpp: In function ‘void det()’: user.cpp:42:7: warning: left operand of comma operator has no effect [-Wunused-value] a,b; ^ user.cpp:42:8: warning: right operand of comma operator has no effect [-Wunused-value] a,b; ^ user.cpp: In function ‘int main()’: user.cpp:65:27: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%d%d",&N,&Q); ^ user.cpp:69:28: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%d",&len); ^ user.cpp:77:30: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%d",&a); ^