Compilare: user.c: In function ‘gcd’: user.c:47:9: warning: ‘return’ with a value, in function returning void [enabled by default] return a; ^ user.c: In function ‘main’: user.c:64:15: warning: unused variable ‘t’ [-Wunused-variable] long long t; ^ user.c:63:19: warning: unused variable ‘c’ [-Wunused-variable] long long a,b,c; ^ user.c:118:11: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(f,"%lld%lld",&a,&b); ^