Compilare: user.c:3:1: warning: return type defaults to ‘int’ [enabled by default] main(){ ^ user.c: In function ‘main’: user.c:8:22: warning: unused variable ‘k’ [-Wunused-variable] int i, j = 0, l = 1, k, N; ^ user.c:5:8: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("transformari.in", "r", stdin); ^ user.c:6:8: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("transformari.out", "w", stdout); ^ user.c:10:6: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &N); ^