Compilare: user.c: In function ‘main’: user.c:21:5: warning: implicit declaration of function ‘fabs’ [-Wimplicit-function-declaration] if(fabs((H*12)-M)<=0.001){ ^ user.c:21:8: warning: incompatible implicit declaration of built-in function ‘fabs’ [enabled by default] if(fabs((H*12)-M)<=0.001){ ^ user.c:12:7: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(file1, "%d", &N); ^ user.c:15:11: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(file1, "%lf", &H); ^ user.c:16:11: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(file1, "%lf", &M); ^