I want to have a new random number every time to print it, but it prints the same on. I tried so many thing, but I can't figure out what's wrong. Help me, please!
import 'dart:math';
int next_int() { return new Random().nextInt(100); }
void main()
{
List<int> list = [next_int(), next_int(), next_int()];
// expected new int each time but got the same one
for (var i = 0; i < 3; i++)
{
List<int> cur_list = new List.from(list);
print(cur_list[0]);
}
}
This code will work as you expect:
import 'dart:math';
int next_int() { return new Random().nextInt(100); }
void main()
{
List<int> list = [next_int(), next_int(), next_int()];
// expected new int each time but got the same one
for (var i = 0; i < 3; i++)
{
List<int> cur_list = new List.from(list);
print(cur_list[i]); // <= Use the index value stored in "i" instead of 0
}
}
Related
import 'dart:io';
import 'dart:math';
void main() {
String? name;
int numberWish = 0;
int myNumber = 90;
Random random = Random();
print("Hi! Let's play a game! \n What is your name?");
name = stdin.readLineSync();
print("So, $name, write below the number, And If it will be the same number, that I wish, you are the winner and hve the chance to choose gift!");
numberWish = int.parse(stdin.readLineSync()!);
for (var index = 0; index < numberWish; index++) {
myNumber = random.nextInt(numberWish);
print(myNumber);
}
if (myNumber == numberWish) {
print("You are the winner");
} else {
print("Sorry :(");
}
}
It is simple game, where I write the number and if it is the same with randomnumber, I win.
So I run it several times, but I can not win. Random specially choose numbers, which is different from my wished number. I think it is my fault :D. How can I fix it?
here is my code
import 'dart:io';
import 'dart:math';
void main() {
bool flag = false;
for (int i = 0; i < 100; i++) {
gameCode();
if (userNumber == computerNumber) {
flag = true;
break;
}
}
}
int randomNumber(number) {
Random randNumber = Random();
int random = randNumber.nextInt(number);
return random;
}
gameCode() {
int computerNumber = randomNumber(9);
print("start guessing the number : ");
int userNumber = int.parse(stdin.readLineSync()!);
if (userNumber == computerNumber) {
print("You got it");
}
}
in this code you can see gameCode function. in that function there is two value that i need to use in main function.so how do i return those two keyword from that function ?
//userNumber // computerNumber
this is the variable that i want to return from that code
Dart not support return multiple values in function, you can return it with array, map, or you can use third lib tuple
Dart does not support returning multiple values in the current latest version. I would in your case recommend creating a class for the specific purpose of define the result from gameCode(). So something like this:
class GameCodeResult {
int userNumber;
int computerNumber;
GameCodeResult({
required this.userNumber,
required this.computerNumber,
});
}
Which we can then use like this in your program:
import 'dart:io';
import 'dart:math';
void main() {
bool flag = false;
for (int i = 0; i < 100; i++) {
GameCodeResult result = gameCode();
if (result.userNumber == result.computerNumber) {
flag = true;
break;
}
}
}
final _random = Random();
int randomNumber(int maxNumber) => _random.nextInt(maxNumber);
GameCodeResult gameCode() {
int computerNumber = randomNumber(9);
print("start guessing the number : ");
int userNumber = int.parse(stdin.readLineSync()!);
if (userNumber == computerNumber) {
print("You got it");
}
return GameCodeResult(userNumber: userNumber, computerNumber: computerNumber);
}
Note, I also fixed your randomNumber() method since it is not recommended to generate a new Random() object for each new random number you want. We should instead reuse an instance of Random in our program.
Please refer to below code
import 'dart:io';
import 'dart:math';
void main() {
bool flag = false;
for (int i = 0; i < 100; i++) {
Map<String, dynamic> res = gameCode();
print(res);
if (res['user_number'] == res['computer_number']) {
flag = true;
break;
}
}
}
int randomNumber(number) {
Random randNumber = Random();
int random = randNumber.nextInt(number);
return random;
}
Map<String, dynamic> gameCode() {
int computerNumber = randomNumber(9);
print("start guessing the number : ");
int userNumber =
int.parse(stdin.readLineSync()!);
if (userNumber == computerNumber) {
print("You got it");
}
return {
"computer_number": computerNumber,
"user_number": userNumber,
};
}
Edit: i know, always call the first element on list, it isnt the point. i want to call numbers[0] func. and it regenerate new int.actually codes are not same which mine, i have a custom class which based on functions with random int and i need to use list of my custom class , so if i use func in list it will be awesome, how can i make new numbers list each time. when app start list regenerated, but i want when i call the list, it will regenerated
i want to print new int for each print but it prints same int , i tried so many thing and i cant figure out
void main{
int ramdomint(){
final _random = new Random();
int _num = _random.nextInt(100);
return _num;
}
List<int> numbers=[ramdomint(),ramdomint(),ramdomint()];
void printNums(){
for(var i=0;i<3;i++){
List<int> newNumbers =new List.from(numbers); //what can i use for this?
print(newNumbers[0]); //edit:i dont want [i], iwant to use ewNumbers[0] for new int for each time
}
}
printNums();
// expected new int for each but same one
}
solution from a friend:
import 'dart:math';
int get ramdomint => Random().nextInt(100);
List<int> get numbers => [ramdomint, ramdomint, ramdomint];
void main() {
for (var i = 0; i < 3; i++) {
print(numbers[0]);
}
}
Do not nest functions. Move ramdomint and printNums outside main function.
Add an empty list of arguments to the main function.
printNums: pass list of numbers as an argument.
printNums: you don't need to copy the list to the newNumbers if you want only to display the content of the list.
printNums: the problem is, you access only first element of the list (with 0 index).
import 'dart:math';
void main() {
List<int> numbers = [ramdomint(), ramdomint(), ramdomint()];
printNums(numbers);
}
int ramdomint() => Random().nextInt(100);
void printNums(List<int> numbers) {
// Easier way:
for (int item in numbers) {
print(item);
}
// Your way:
for (int i = 0; i < numbers.length; i++) {
print(numbers[i]);
}
}
EDIT:
According to #jamesdlin's comment, you can extend list class to randomize unique values in the list:
import 'dart:math';
void main() {
var numbers = <int>[]..randomize();
printNums(numbers);
}
void printNums(List<int> numbers) {
// Easier way:
for (int item in numbers) {
print(item);
}
// Your way:
for (int i = 0; i < numbers.length; i++) {
print(numbers[i]);
}
}
extension on List<int> {
void randomize({
int length = 3,
int maxValue = 100,
}) {
final generator = Random();
for (var i = 0; i < length; i++) {
add(generator.nextInt(maxValue));
}
}
}
The Problem here is that you are creating a list from the numbers list and accessing only the first element.
So it always prints the first element.
import 'dart:math';
void main() {
int ramdomint(){
final _random = new Random();
int _num = _random.nextInt(100);
return _num;
}
List<int> numbers=[ramdomint(),ramdomint(),ramdomint()];
void printNums(){
for(var i=0;i<3;i++){
print(numbers[i]);
}
}
printNums();
}
Don't want newNumbers, because it is already in List.
and the usage of List.from() - Documentation
Hope that works!
I'm not sure if I'm not understanding this correctly, but here's my code. I'm trying to get the StreamTransformer to act on the stream, but the values still come out the other end untouched.
Note: I added the .map() function, which does nothing, just to make sure it wasn't a missing map function that was my issue. I'm leaving it here just in case.
import 'dart:async';
void main() {
int count = 0;
var counterController = new StreamController();
counterController.stream.listen((value) => print(value));
void increment() {
counterController.add(count++);
}
final transformToString =
new StreamTransformer.fromHandlers(handleData: (number, sink) {
if (number.runtimeType == int) {
sink.add("The counter is at $number!");
} else {
sink.addError("$number is not an int!");
}
});
counterController.stream.map((input) => input).transform(transformToString);
for(int i=0; i < 10; i++){
increment();
}
}
Link to the code in DartPad
As was mentioned by my instructor, the transform function creates out a new stream. So I have to attach a listener to the transformed stream, I can't expect transformed values to come out of the old stream. So the modified code below works.
import 'dart:async';
void main() {
...
counterController.stream.map((input) => input)
.transform(transformToString).listen(print);
for(int i=0; i < 10; i++){
increment();
}
}
Hi guys So i have this problem.. i wanted to print a calendar, utilizing the Calendar API.
condition:
user inputs a Year, anInteger between 1000 - 9999.
then it will output the calendar of that year and 2 more succeeding years.
so if i input 2012 it will output the Calendar of 2012 , 2013 and 2014.
here is the catch it must be SIDEWAYS!
package lessons;
import java.text.DateFormatSymbols;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.GregorianCalendar;
import java.util.Scanner;
public class lesson3 {
static String[] days = {"SUN","MON","TUE","WED","THU","FRI","SAT"};
static int counter = 0;
public static void main(String[] args) {
GregorianCalendar gcal = new GregorianCalendar();
Scanner scanner = new Scanner(System.in);
System.out.print("Year: ");
int input = scanner.nextInt(); //month input
//System.out.print("YEAR (): ");
//int input2 = scanner.nextInt();
scanner.close();
int year = input;
gcal.set(Calendar.YEAR,input);
for(int monthCount = 0;monthCount<12;monthCount++){
gcal.set(Calendar.MONTH,monthCount); // month counter 0 - 11 producing jan to dec.
monthCheck(monthCount); // converting months to readable names
int x = gcal.get(Calendar.DAY_OF_WEEK);
int max = gcal.getActualMaximum(Calendar.DAY_OF_MONTH);
for(int i = 0;i<days.length;i++){
System.out.printf("%8s",days[i]);
}
System.out.println("");
for(int i = 0; i < x-1;i++){
System.out.printf("%8s","");
counter++;
if(counter%7==0){
System.out.println("");
}
}
for(int i = 1;i<=max;i++){
System.out.printf("%8s",i);
counter++;
if(counter%7==0){
System.out.println("");
}
}
System.out.println("");
//System.out.println(x);
}
}
static void monthCheck(int monthCount){
ArrayList monthsList = new ArrayList<String>();
String[] months = new DateFormatSymbols().getMonths();
for (int i = 0; i < months.length-1; i++) {
String monthArr = months[i];
monthsList.add(months[i]);
}
System.out.println(months[monthCount]);
}
}
This is what i can do with the code Above, click here!
this is what i am aiming for now. CLICK HERE!