Eroare de compilare: user.c: In function ‘main’: user.c:20: error: ‘for’ loop initial declarations are only allowed in C99 mode user.c:20: note: use option -std=c99 or -std=gnu99 to compile your code user.c:15: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result user.c:16: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result user.c:18: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result user.c:21: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result