Compilare: user.c:2:1: warning: return type defaults to ‘int’ [enabled by default] main() ^ user.c: In function ‘main’: user.c:15:1: warning: implicit declaration of function ‘cmmdc’ [-Wimplicit-function-declaration] x = cmmdc(a,b); ^ user.c:13:7: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(in,"%d",&a); ^ user.c:14:7: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(in,"%d",&b); ^