Compilare: user.c: In function ‘main’: user.c:17: warning: format ‘%d’ expects type ‘int *’, but argument 2 has type ‘int’ user.c:19: warning: format ‘%d’ expects type ‘int *’, but argument 2 has type ‘int’ user.c:19: warning: format ‘%d’ expects type ‘int *’, but argument 3 has type ‘int’ 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:17: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result user.c:19: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result user.c:17: warning: ‘n’ is used uninitialized in this function user.c:19: warning: ‘a’ may be used uninitialized in this function user.c:19: warning: ‘b’ may be used uninitialized in this function