Compilare: user.c: In function ‘main’: user.c:50:3: warning: implicit declaration of function ‘memset’ [-Wimplicit-function-declaration] memset(ut1, -1, sizeof ut1); ^ user.c:50:3: warning: incompatible implicit declaration of built-in function ‘memset’ [enabled by default] user.c:49:9: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(in, "%d%d", &n, &m); ^ user.c:53:11: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(in, "%d%d", &x, &y); ^