Compilare: user.c:3:1: warning: return type defaults to ‘int’ [enabled by default] main() ^ user.c: In function ‘main’: user.c:21:4: warning: implicit declaration of function ‘cmmdc’ [-Wimplicit-function-declaration] if(cmmdc(i,j) ==1) ^ user.c:27:2: warning: implicit declaration of function ‘close’ [-Wimplicit-function-declaration] close(in); ^ user.c:13:8: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(in,"%d",&n); ^