Compilare: user.c: In function ‘cer_a’: user.c:13:1: warning: control reaches end of non-void function [-Wreturn-type] } ^ user.c: In function ‘cer_b’: user.c:22:1: warning: control reaches end of non-void function [-Wreturn-type] } ^ user.c: In function ‘main’: user.c:30:9: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin,"%d%d ",&m,&n); ^ user.c:36:11: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(fin,"\n"); ^