Compilare: main.c: In function 'main': main.c:39:5: warning: ignoring return value of 'fgets', declared with attribute warn_unused_result [-Wunused-result] fgets(s1, 2000000, fin); ^~~~~~~~~~~~~~~~~~~~~~~ main.c:41:5: warning: ignoring return value of 'fgets', declared with attribute warn_unused_result [-Wunused-result] fgets(s2, 2000000, fin); ^~~~~~~~~~~~~~~~~~~~~~~