Compilare: user.c: In function ‘main’: user.c:12:5: warning: implicit declaration of function ‘close’ [-Wimplicit-function-declaration] close(f1); ^ user.c:9:12: warning: unused variable ‘j’ [-Wunused-variable] int f, j; ^ user.c:6:18: warning: unused variable ‘pos’ [-Wunused-variable] int total=0, pos; ^ user.c:11:11: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f1,"%d %d",&a,&b); ^