Compilare: user.c: In function ‘main’: user.c:16:5: warning: implicit declaration of function ‘memset’ [-Wimplicit-function-declaration] memset(fr, 0, 4 * n); ^ user.c:16:5: warning: incompatible implicit declaration of built-in function ‘memset’ [enabled by default] user.c:7:13: warning: unused variable ‘j’ [-Wunused-variable] int n, i, j, s, p1, p2; ^ user.c:8:9: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(in, "%d", &n); ^ user.c:10:11: warning: ignoring return value of ‘fscanf’, declared with attribute warn_unused_result [-Wunused-result] fscanf(in, "%d", &v[i]); ^