Dart - How to concatenate a String and my integer - string

How can I concatenate my String and the int in the lines:
print('Computer is moving to ' + (i + 1));
and print("Computer is moving to " + (i + 1));
I cant figure it out because the error keeps saying "The argument type 'int' can't be assigned to the parameter type 'String'
void getComputerMove() {
int move;
// First see if there's a move O can make to win
for (int i = 0; i < boardSize; i++) {
if (_mBoard[i] != humanPlayer && _mBoard[i] != computerPlayer) {
String curr = _mBoard[i];
_mBoard[i] = computerPlayer;
if (checkWinner() == 3) {
print('Computer is moving to ' + (i + 1));
return;
} else
_mBoard[i] = curr;
}
}
// See if there's a move O can make to block X from winning
for (int i = 0; i < boardSize; i++) {
if (_mBoard[i] != humanPlayer && _mBoard[i] != computerPlayer) {
String curr = _mBoard[i]; // Save the current number
_mBoard[i] = humanPlayer;
if (checkWinner() == 2) {
_mBoard[i] = computerPlayer;
print("Computer is moving to " + (i + 1));
return;
} else
_mBoard[i] = curr;
}
}
}

With string interpolation:
print("Computer is moving to ${i + 1}");
Or just call toString():
print("Computer is moving to " + (i + 1).toString());

You can simply use .toString which will convert your integer to String :
void main(){
String str1 = 'Welcome to Matrix number ';
int n = 24;
//concatenate str1 and n
String result = str1 + n.toString();
print(result);
}
And in your case it's gonna be like this :
print("Computer is moving to " + (i + 1).toString());

Related

Encode string "aaa" to "3[a]"

give a string s, encode it by the format: "aaa" to "3[a]". The length of encoded string should the shortest.
example: "abbabb" to "2[a2[b]]"
update: suppose the string only contains lowercase letters
update: here is my code in c++, but it's slow. I know one of the improvement is using KMP to compute if the current string is combined by a repeat string.
// this function is used to check if a string is combined by repeating a substring.
// Also Here can be replaced by doing KMP algorithm for whole string to improvement
bool checkRepeating(string& s, int l, int r, int start, int end){
if((end-start+1)%(r-l+1) != 0)
return false;
int len = r-l+1;
bool res = true;
for(int i=start; i<=end; i++){
if(s[(i-start)%len+l] != s[i]){
res = false;
break;
}
}
return res;
}
// this function is used to get the length of the current number
int getLength(int l1, int l2){
return (int)(log10(l2/l1+1)+1);
}
string shortestEncodeString(string s){
int len = s.length();
vector< vector<int> > res(len, vector<int>(len, 0));
//Initial the matrix
for(int i=0; i<len; i++){
for(int j=0; j<=i; j++){
res[j][i] = i-j+1;
}
}
unordered_map<string, string> record;
for(int i=0; i<len; i++){
for(int j=i; j>=0; j--){
string temp = s.substr(j, i-j+1);
/* if the current substring has showed before, then no need to compute again
* Here is a example for this part: if the string is "abcabc".
* if we see the second "abc", then no need to compute again, just use the
* result from first "abc".
**/
if(record.find(temp) != record.end()){
res[j][i] = record[temp].size();
continue;
}
string ans = temp;
for(int k=j; k<i; k++){
string str1 = s.substr(j, k-j+1);
string str2 = s.substr(k+1, i-k);
if(res[j][i] > res[j][k] + res[k+1][i]){
res[j][i] = res[j][k]+res[k+1][i];
ans = record[str1] + record[str2];
}
if(checkRepeating(s, j, k, k+1, i) == true && res[j][i] > 2+getLength(k-j+1, i-k)+res[j][k]){
res[j][i] = 2+getLength(k-j+1, i-k)+res[j][k];
ans = to_string((i-j+1)/(k-j+1)) + '[' + record[str1] +']';
}
}
record[temp] = ans;
}
}
return record[s];
}
With very little to start with in terms of a question statement, I took a quick stab at this using JavaScript because it's easy to demonstrate. The comments are in the code, but basically there are alternating stages of joining adjacent elements, run-length checking, joining adjacent elements, and on and on until there is only one element left - the final encoded value.
I hope this helps.
function encode(str) {
var tmp = str.split('');
var arr = [];
do {
if (tmp.length === arr.length) {
// Join adjacent elements
arr.length = 0;
for (var i = 0; i < tmp.length; i += 2) {
if (i < tmp.length - 1) {
arr.push(tmp[i] + tmp[i + 1]);
} else {
arr.push(tmp[i]);
}
}
tmp.length = 0;
} else {
// Swap arrays and clear tmp
arr = tmp.slice();
tmp.length = 0;
}
// Build up the run-length strings
for (var i = 0; i < arr.length;) {
var runlength = runLength(arr, i);
if (runlength > 1) {
tmp.push(runlength + '[' + arr[i] + ']');
} else {
tmp.push(arr[i]);
}
i += runlength;
}
console.log(tmp);
} while (tmp.length > 1);
return tmp.join();
}
// Get the longest run length from a given index
function runLength(arr, ind) {
var count = 1;
for (var i = ind; i < arr.length - 1; i++) {
if (arr[i + 1] === arr[ind]) {
count++;
} else {
break;
}
}
return count;
}
<input id='inp' value='abbabb'>
<button type="submit" onClick='javascript:document.getElementById("result").value=encode(document.getElementById("inp").value)'>Encode</button>
<br>
<input id='result' value='2[a2[b]]'>

encoding and decoding a string

I need to write an application that fist converts a string to unicode and then add 2 to the unicode value to create a new string.
Basically, if the input is: password is RhYxtz, then the output should look like: rcuuyqtf ku TjAzvb
the following code is what I have so far:
public static void main(String[] args){
System.out.print ("Enter text: ");
Scanner scan = new Scanner(System.in);
String text = scan.nextLine();
int length = text.length();
for(int i = 0; i < length; i ++){
char currentChar = text.charAt(i);
int currentChar2 = currentChar+2;
String s = String.format ("\\u%04x", currentChar2);
System.out.println ("Encoded message: " + s);
}
}
The problem is that I don't know how to convert the unicode back into a letter string and how to keep the format the same as the input. Could anyone help me? Thanks.
Unicode code points can be gathered in java 8 as:
public static String encryped(String s) {
int[] cps = s.codePoints()
.mapToInt((cp) -> cp + 2)
.toArray();
return new String(cps, 0, cps.length);
}
or in a loop with codePointAt in earlier versions.
Java char (2 bytes) are UTF-16, and their int value is not always a Unicode symbol aka code point.
Try this:
import java.util.Scanner;
public class Example {
public static void main(String[] args) {
System.out.print ("Enter text: ");
Scanner scan = new Scanner(System.in);
String text = scan.nextLine();
int length = text.length();
String s = "";
for(int i = 0; i < length; i ++){
char currentChar = text.charAt(i);
if (currentChar == ' '){
s += currentChar;
} else {
s += (char) (currentChar + 2);
}
}
System.out.println ("Encoded message: " + s);
}
}
This should work for US ASCII letters:
StringBuilder buf = new StringBuilder(length);
for(int i = 0; i < length; i ++){
char currentChar = text.charAt(i);
if (currentChar < 128 && Character.isLetter(currentChar)) {
if (currentChar == 'y' || currentChar == 'z'
|| currentChar == 'Y' || currentChar == 'Z') {
buf.append((char) (currentChar + 2 - 26));
} else {
buf.append((char) (currentChar + 2));
}
} else {
buf.append(currentChar);
}
}
System.out.println(buf.toString());

sum and substract using char and string only

I have to make a code that sums and subtracts two or more numbers using the + and - chars
I managed to make the sum, but I have no idea on how to make it subtract.
Here is the code (I'm allowed to use the for and while loops only):
int CM = 0, CR = 0, A = 0, PS = 0, PR = 0, LC = 0, D;
char Q, Q1;
String f, S1;
f = caja1.getText();
LC = f.length();
for (int i = 0; i < LC; i++) {
Q = f.charAt(i);
if (Q == '+') {
CM = CM + 1;
} else if (Q == '-') {
CR = CR + 1;
}
}
while (CM > 0 || CM > 0) {
LC = f.length();
for (int i = 0; i < LC; i++) {
Q = f.charAt(i);
if (Q == '+') {
PS = i;
break;
} else {
if (Q == '-') {
PR = i;
break;
}
}
}
S1 = f.substring(0, PS);
D = Integer.parseInt(S1);
A = A + D;
f = f.substring(PS + 1);
CM = CM - 1;
}
D = Integer.parseInt(f);
A = A + D;
salida.setText("resultado" + " " + A + " " + CR + " " + PR + " " + PS);
The following program will solve your problem of performing addition and subtraction in a given equation in String
This sample program is given in java
public class StringAddSub {
public static void main(String[] args) {
//String equation = "100+500-20-80+600+100-50+50";
//String equation = "100";
//String equation = "500-900";
String equation = "800+400";
/** The number fetched from equation on iteration*/
String b = "";
/** The result */
String result = "";
/** Arithmetic operation to be performed */
String previousOperation = "+";
for (int i = 0; i < equation.length(); i++) {
if (equation.charAt(i) == '+') {
result = performOperation(result, b, previousOperation);
previousOperation = "+";
b = "";
} else if (equation.charAt(i) == '-') {
result = performOperation(result, b, previousOperation);
previousOperation = "-";
b = "";
} else {
b = b + equation.charAt(i);
}
}
result = performOperation(result, b, previousOperation);
System.out.println("Print Result : " + result);
}
public static String performOperation(String a, String b, String operation) {
int a1 = 0, b1 = 0, res = 0;
if (a != null && !a.equals("")) {
a1 = Integer.parseInt(a);
}
if (b != null && !b.equals("")) {
b1 = Integer.parseInt(b);
}
if (operation.equals("+")) {
res = a1 + b1;
}
if (operation.equals("-")) {
res = a1 - b1;
}
return String.valueOf(res);
}
}

How do I make so that when I input a value into a scanner if it is not an integer it won't give me an error?

I am writing a program that does simple math problems. What I am trying to do is to make it so that even if I input a string into the the scanner level it will not give me an error. The level is to choose the difficulty of the math problems. I have tried parseInt, but am at a loss of what to do now.
import java.util.Random;
import java.util.Scanner;
public class Test {
static Scanner keyboard = new Scanner(System.in);
static Random generator = new Random();
public static void main(String[] args) {
String level = intro();//This method intorduces the program,
questions(level);//This does the actual computation.
}
public static String intro() {
System.out.println("HI - I am your friendly arithmetic tutor.");
System.out.print("What is your name? ");
String name = keyboard.nextLine();
System.out.print("What level do you choose? ");
String level = keyboard.nextLine();
System.out.println("OK " + name + ", here are ten exercises for you at the level " + level + ".");
System.out.println("Good luck.");
return level;
}
public static void questions(String level) {
int value = 0, random1 = 0, random2 = 0;
int r = 0, score = 0;
int x = Integer.parseInt("level");
if (x==1) {
r = 4;
}
else if(x==2) {
r = 9;
}
else if(x==3) {
r = 50;
}
for (int i = 0; i<10; i++) {
random1 = generator.nextInt(r);//first random number.
random2 = generator.nextInt(r);//second random number.
System.out.print(random1 + " + " + random2 + " = ");
int ans = keyboard.nextInt();
if((random1 + random2)== ans) {
System.out.println("Your answer is correct!");
score+=1;
}
else if ((random1 + random2)!= ans) {
System.out.println("Your answer is wrong!");
}
}
if (score==10 || score==9) {
if (score==10 && x == 3) {
System.out.println("This system is of no further use.");
}
else {
System.out.println("Choose a higher difficulty");
}
System.out.println("You got " + score + " out or 10");
}
else if (score<=8 && score>=6) {
System.out.println("You got " + score + " out or 10");
System.out.println("Do the test again");
}
else if (score>6) {
System.out.println("You got " + score + " out or 10");
System.out.println("Come back for extra lessons");
}
}
}
The first error I see is that you tried to Integer.parseInt() a String "level" instead of the String variable named level
int x = Integer.parseInt("level");
should be
int x = Integer.parseInt(level);
Also, when defining level you can use keyboard.nextInt instead of keyboard.nextLine
String level = keyboard.nextInt();
Then, you wouldn't have to do an Integer.parseInt() operation later on

Text version compare in FCKEditor

Am using Fck editor to write content. Am storing the text as versions in db. I want to highlight those changes in versions when loading the text in FCK Editor.
How to compare the text....
How to show any text that has been deleted in strike through mode.
Please help me/...
Try google's diff-patch algorithm http://code.google.com/p/google-diff-match-patch/
Take both previous and current version of the text and store it into two parameters. Pass the two parameters to the following function.
function diffString(o, n) {
o = o.replace(/<[^<|>]+?>| /gi, '');
n = n.replace(/<[^<|>]+?>| /gi, '');
var out = diff(o == "" ? [] : o.split(/\s+/), n == "" ? [] : n.split(/\s+/));
var str = "";
var oSpace = o.match(/\s+/g);
if (oSpace == null) {
oSpace = ["\n"];
} else {
oSpace.push("\n");
}
var nSpace = n.match(/\s+/g);
if (nSpace == null) {
nSpace = ["\n"];
} else {
nSpace.push("\n");
}
if (out.n.length == 0) {
for (var i = 0; i < out.o.length; i++) {
str += '<span style="background-color:#F00;"><del>' + escape(out.o[i]) + oSpace[i] + "</del></span>";
}
} else {
if (out.n[0].text == null) {
for (n = 0; n < out.o.length && out.o[n].text == null; n++) {
str += '<span style="background-color:#F00;"><del>' + escape(out.o[n]) + oSpace[n] + "</del></span>";
}
}
for (var i = 0; i < out.n.length; i++) {
if (out.n[i].text == null) {
str += '<span style="background-color:#0C0;"><ins>' + escape(out.n[i]) + nSpace[i] + "</ins></span>";
} else {
var pre = "";
for (n = out.n[i].row + 1; n < out.o.length && out.o[n].text == null; n++) {
pre += '<span style="background-color:#F00;"><del>' + escape(out.o[n]) + oSpace[n] + "</del></span>";
}
str += " " + out.n[i].text + nSpace[i] + pre;
}
}
}
return str;
}
this returns an html in which new text is marked green and deleted text as red + striked out.

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