Compilare: user.cpp: In function ‘int main()’: user.cpp:4:69: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] int dif[BASE * 2]; int main() { freopen("fsb.in", "r", stdin); freopen("fsb.out", "w", stdout); int d, zero, unu, cnt, i, n; scanf("%d\n%s", &n, s + 1); zero = unu = cnt = 0; dif[BASE] = 1; for(i = 1; i <= n; ++ i) { if(s[i] == '0') ++ zero; else ++ unu; d = unu - zero; cnt += dif[d + BASE]; ++ dif[d + BASE]; } printf("%d\n", cnt); return 0; } ^ user.cpp:4:106: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] int dif[BASE * 2]; int main() { freopen("fsb.in", "r", stdin); freopen("fsb.out", "w", stdout); int d, zero, unu, cnt, i, n; scanf("%d\n%s", &n, s + 1); zero = unu = cnt = 0; dif[BASE] = 1; for(i = 1; i <= n; ++ i) { if(s[i] == '0') ++ zero; else ++ unu; d = unu - zero; cnt += dif[d + BASE]; ++ dif[d + BASE]; } printf("%d\n", cnt); return 0; } ^ user.cpp:4:173: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] int dif[BASE * 2]; int main() { freopen("fsb.in", "r", stdin); freopen("fsb.out", "w", stdout); int d, zero, unu, cnt, i, n; scanf("%d\n%s", &n, s + 1); zero = unu = cnt = 0; dif[BASE] = 1; for(i = 1; i <= n; ++ i) { if(s[i] == '0') ++ zero; else ++ unu; d = unu - zero; cnt += dif[d + BASE]; ++ dif[d + BASE]; } printf("%d\n", cnt); return 0; } ^