Compilare: user.c: In function ‘main’: user.c:17:5: warning: implicit declaration of function ‘malloc’ [-Wimplicit-function-declaration] char *sieve = (char*)malloc((B + 1) * sizeof(char)); ^ user.c:17:26: warning: incompatible implicit declaration of built-in function ‘malloc’ [enabled by default] char *sieve = (char*)malloc((B + 1) * sizeof(char)); ^ user.c:66:12: warning: ‘bj’ may be used uninitialized in this function [-Wmaybe-uninitialized] fprintf(fout, "%d %d\n", bi, bj); ^ user.c:66:12: warning: ‘bi’ may be used uninitialized in this function [-Wmaybe-uninitialized]