Compilare: main.c: In function 'main': main.c:4:5: warning: ignoring return value of 'freopen', declared with attribute warn_unused_result [-Wunused-result] freopen( "ssm.in", "r", stdin ); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.c:5:5: warning: ignoring return value of 'freopen', declared with attribute warn_unused_result [-Wunused-result] freopen( "ssm.out", "w", stdout ); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ main.c:7:5: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result] scanf( "%d", &n ); ^~~~~~~~~~~~~~~~~ main.c:12:9: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result] scanf( "%d", &a ); ^~~~~~~~~~~~~~~~~