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Print a message only once after iterating 2d array

import java.util.Scanner;
public class Note {
public static void main(String[] args) {
String etudiants[][] = new String[1][4];
Scanner saisie = new Scanner(System.in);
for (int i = 0; i < 1; i++) {
System.out.print("\n\nEtudiant BTI00" + (i + 1) + "\n\n");
for (int j = 0; j < 4; j++) {
if (j == 0) {
System.out.print("\n\tCode de l'etudiant : ");
} else if (j == 1) {
System.out.print("\n\tNom etudiant : ");
} else if (j == 2) {
System.out.print("\n\tNote Maths : ");
} else if (j == 3) {
System.out.print("\n\tNote Francais : ");
} else {
System.out.print("\n\tChamps inexistant!");
}
etudiants[i][j] = saisie.nextLine();
}
}
System.out.print("\n\tEtudiants Enregistres : \n\n");
// System.out.print("\tCode\tNom\t\tMaths\tFrancais\n\n");
for (int i = 0; i < 1; i++) {
for (int j = 0; j < 4; j++) {
System.out.print("\t" + etudiants[i][j] + " ");
}
}
System.out.println();
System.out.print("\n\tEntrez code etudiant : ");
String recherche = saisie.nextLine();
boolean trouve = false;
for (int i = 0; i < 1; i++) {
for (int j = 0; j < 4; j++) {
if (recherche.equals(etudiants[i][0])) {
trouve = true;
System.out.print("\n\tCode etudiant correct!");
String math = etudiants[i][2];
String francais = etudiants[i][3];
Double m = new Double(math);
double mathConv = m.doubleValue();
Double f = new Double(francais);
double francaisConv = f.doubleValue();
double moyenne = (mathConv + francaisConv) / 2;
System.out.print("\n\tMoyenne de l'etudiant : " + moyenne);
System.out.print("\n\tEtudiant : " + etudiants[i][j]);
if (moyenne <= 40) {
System.out.print("\n\tEchec!");
} else if (moyenne > 40 && moyenne < 70) {
System.out.print("\n\tReprise!");
} else {
System.out.print("\n\tSucces!");
}
} if (!trouve) {
System.out.print("\n\tCode etudiant incorrect!");
}
}
}
}
}
I need to display only one message after entering the code etudiant but istead it displays the message 4 times. The loop should only iterate through the first column of each line and compares it to what the user entered.

The indexing variable (j) of the last inner for-loop (for (int j = 0; j < 4; j++) {) is never used inside the loop, so you actually do not need that loop at all. General styling issues of your sample aside, you should rewrite the last loop like this:
for (int i = 0; i < 1; i++) {
// throw away this
//for (int j = 0; j < 4; j++) {
if (recherche.equals(etudiants[i][0])) {
trouve = true;
// ... rest of the code like you currently have it
// You probably do not need this line too,
// because you have almost the same in your second loop
//System.out.print("\n\tEtudiant : " + etudiants[i][j]);
}
}

Printing message only once after iterating through the first column of a 2d array

import java.util.Scanner;
public class Grade{
public static void main(String[] args) {
String students[][] = new String[2][4];
Scanner input = new Scanner(System.in);
for (int i = 0; i < 2; i++) {
System.out.print("\n\nStudent 00" + (i + 1) + "\n\n");
for (int j = 0; j < 4; j++) {
if (j == 0) {
System.out.print("\n\tStudent Code : ");
} else if (j == 1) {
System.out.print("\n\tName : ");
} else if (j == 2) {
System.out.print("\n\tMaths Grade : ");
} else if (j == 3) {
System.out.print("\n\tFrench Grade : ");
} else {
System.out.print("\n\tNonexistent field!\n");
}
students[i][j] = input.nextLine();
}
}
System.out.print("\n\tRegistered Students : \n\n");
System.out.print("\tCODE\tFULL NAME\tMATHS\tFRENCH\n\n");
for (int i = 0; i < 2; i++) {
for (int j = 0; j < 4; j++) {
System.out.print("\t" + students[i][j] + " ");
}
System.out.println();
}
//Ask for student code.
System.out.print("\n\tStudent Code : ");
String search= input.nextLine();
boolean found = false;
for (int i = 0; i < 2; i++) {
for (int j = 0; j < 4; j++) {
// found= true;
if (search.equals(students[i][0])) {
found = true;
System.out.print("\n\tStudent Code Found!\n");
String math = students[i][2];
String french = students[i][3];
Double m = new Double(math);
double mathConv = m.doubleValue();
Double f = new Double(french);
double frenchConv = f.doubleValue();
double average = (mathConv + frenchConv) / 2;
System.out.print("\n\tMoyenne de l'etudiant : " + average + "\n");
if (average <= 40) {
System.out.print("\n\tFailure!\n");
} else if (average > 40 && average < 70) {
System.out.print("\n\tReprisal!\n");
} else {
System.out.print("\n\tSuccess!\n");
}
}
else if (!search.equals(students[i][0])) {
found = false;
System.out.print("\n\tCode incorrect!\n");
}
}
}
}
}
I need to display only one message after entering the code etudiant but istead it displays the message 4 times. The loop should only iterate through the first column of each line and compares it to what the user entered.

When you iterate for the search you don't need the second loop to iterate over the attributes, because you don't use it
System.out.print("\n\tStudent Code : ");
String search = input.nextLine();
boolean found = false;
for (int i = 0; i < 2; i++) {
// for (int j = 0; j < 4; j++) { //you don't need this loop

Change this:
for (int j = 0; j < 4; j++)
to this:
for (int j = 0; j < 1; j++)
as we want to run that loop only once.
Alternatively, you can remove the j loop altogether.

it's recommended you use the length argument for those arrays, that way if you ever change the size, the loop won't break, in this case you can just get the first element of the array, and then iterate through that. So intead of
for (int i = 0; i < 2; i++) {
System.out.print("\n\nStudent 00" + (i + 1) + "\n\n");
for (int j = 0; j < 4; j++) {
if (j == 0) {
System.out.print("\n\tStudent Code : ");
} else if (j == 1) {
System.out.print("\n\tName : ");
} else if (j == 2) {
System.out.print("\n\tMaths Grade : ");
} else if (j == 3) {
System.out.print("\n\tFrench Grade : ");
} else {
System.out.print("\n\tNonexistent field!\n");
}
students[i][j] = input.nextLine();
}
}
you can say
System.out.print("\n\nStudent 001" + "\n\n");
for (int j = 0; j < students[0].length; j++) {
if (j == 0) {
System.out.print("\n\tStudent Code : ");
} else if (j == 1) {
System.out.print("\n\tName : ");
} else if (j == 2) {
System.out.print("\n\tMaths Grade : ");
} else if (j == 3) {
System.out.print("\n\tFrench Grade : ");
} else {
System.out.print("\n\tNonexistent field!\n");
}
students[0][j] = input.nextLine();
}

String,which repeats ,but not starts from the beginning in Java (diamond pattern

This is the work that i done so far:I have to print diamond pattern which always starts with uppercase from string, which repeats,but not always starts from the beginning.
public static void main(String[] args) {
Scanner keyboard = new Scanner(System.in);
String userInput = keyboard.next();
userInput = Character.toUpperCase(userInput.charAt(0)) + userInput.substring(1);
int i;
int j;
if (userInput.length() % 2 != 0) {
for(i = 1; i < userInput.length(); i += 2) {
for(j = 0; j < userInput.length() - 1 - i / 2; ++j) {
System.out.print(" ");
}
for(j = 0; j < i; ++j) {
System.out.print(userInput.charAt(j));
}
System.out.println("");
}
for(i = userInput.length(); i > 0; i -= 2) {
for(j = 0; j < userInput.length() - 1 - i / 2; ++j) {
System.out.print(" ");
}
for(j = 0; j < i; ++j) {
System.out.print(userInput.charAt(j));
}
System.out.print("\n");
}
} else {
for(i = 2; i < userInput.length(); i += 2) {
for(j = 0; j < userInput.length() - 1 - i / 2; ++j) {
System.out.print(" ");
}
for(j = 0; j < i; ++j) {
System.out.print(userInput.charAt(j));
}
System.out.println("");
}
for(i = userInput.length(); i > 0; i -= 2) {
for(j = 0; j < userInput.length() - 1 - i / 2; ++j) {
System.out.print(" ");
}
for(j = 0; j < i; ++j) {
System.out.print(userInput.charAt(j));
}
System.out.print("\n");
}
}
}
For example my input is "Peter".
So my output is:
P
Pet
Peter
Pet
P
but it must be:
P
Ete
Rpete
Rpe
T
I dont know what to change to make this work

Here's a shorter version of your code:
public static void main(String[] args) {
String userInput = "Peter";
int length = userInput.length();
int m, j, i, n = 0;
for (m = length % 2 > 0 ? 1 : 2; m < length * 2; m += 2) {
i = m < length ? m : length * 2 - m;
for (j = 0; j < length - 1 - i / 2; ++j) {
System.out.print(" ");
}
for(j = 0; j < i; ++j) {
char c = userInput.charAt(n++ % length);
c = j == 0 ? Character.toUpperCase(c) : Character.toLowerCase(c);
System.out.print(c);
}
System.out.println("");
}
}

You need some few changes:
Declare int n=0; after int j;
Always print userInput.charAt(n++ % userInput.length()) instead of charAt(j)
In order to get only the first character in line in uppercase:
char c = userInput.charAt(n++ % userInput.length());
c = j == 0 ? Character.toUpperCase(c) : Character.toLowerCase(c);
System.out.print(c);
Check the modulo operator.
With these changes, you'll get this output:
P
Ete
Rpete
Rpe
T

Given the fact that the input itself gets printed in a cylic manner, we can make use out of it. My proposal would be to concatenate the input string and print out the substrings which are determined by the structure of the diamond pattern.
public static void main(String[] args) {
Scanner keyboard = new Scanner(System.in);
String userInput = keyboard.next();
String concatenated = userInput;
// build up the index array
int i, cumSum = 0;
ArrayList<Integer> helperIndex = new ArrayList<>();
for(i = 1; i < userInput.length(); i += 2) {
helperIndex.add(i);
cumSum += i;
}
for(i = userInput.length(); i > 0; i -= 2) {
helperIndex.add(i);
cumSum += i;
}
int numOfWordRepitition = cumSum / userInput.length() ;
for (i = 0; i < numOfWordRepitition; i++){
concatenated += userInput;
}
// print out diamond
String substr;
int prev = helperIndex.get(0);
int next = helperIndex.get(0);
substr = concatenated.substring(0 , helperIndex.get(0));
System.out.println(Character.toUpperCase(substr.charAt(0)) + substr.substring(1));
for(i = 1; i < userInput.length(); i++){
next += helperIndex.get(i);
substr = concatenated.substring(prev , next);
substr = Character.toUpperCase(substr.charAt(0)) + substr.substring(1);
System.out.println(substr);
prev = next;
}
}

replace every second line of my triangle with a blank line for loops

instead of getting a full triangle with 5 lines of "*" how do I replace every second line with a blank line, e.g. to look like this
5
555
55555
This is my code:
for(int i = 0; i < 5; i++) {
for(int j = i; j < 5; j++) {
System.out.print(" ");
}
for(int k = 0; k <= (i*2); k++) {
System.out.print("5");
}
System.out.println();
}

you need small modification in your code and you can get what you want.
for(int i = 0; i < 5; i++) {
for(int j = i; j < 5; j++) {
System.out.print(" ");
}
for(int k = 0; k <= (i*2); k++) {
if(i%2==0)
System.out.print("*");
}
System.out.println();
}
check it out.

Just test for i % 2
for(int i = 0; i < 5; i++) {
for(int j = i; j < 5; j++) {
System.out.print(" ");
}
for(int k = 0; k <= (i*2); k++) {
System.out.print(i % 2 == 0 ? "*" : " ");
}
System.out.println();
}
edit
If you want to print 5 instead or * then modify the code to use 5

Check this:
int num= 5; // 'num' denotes the number of lines
int numOfSpaces;
for(int i = 1; i <= num; i++) {
if( i%2 != 0) // checks whether the line number is odd. If odd, prints '*'
{
numOfSpaces = (num-i) / 2; // find the number of blank spaces
for(int j = 1; j <= numOfSpaces; j++) {
System.out.print(" ");
}
for(int k = 1; k <= i; k++) { // number of '*'s to be printed = current line number = i
System.out.print("*");
}
System.out.println();
}
else{
System.out.println(); // leaves every second line blank (ie.,if line number is even.)
}
}

//try this code. It may help you to achieve your output
[Check screen shot for the output of the below code][1]
for (int i = 0; i < 5; i++)
{
for (int j = 0; j < 5 - i; j++)
{
System.out.print(" ");
}
for (int k = 0; k <= i; k++)
{
if(i%2!=0)
{
System.out.print(" ");
}
else{
System.out.print("* ");
}
}
System.out.println();
}

The Code below is Working now.
A simple if condition will solve your problem. Just check if the
value of i is divisible by 2. If it is true then print a
blank line. Else Print * and you are done!
* will be printed on 1st, 3rd and 5th lines.
Blank Space will be printed on 2nd and 4th lines.
public class PrintPattern{
public static void main(String []args){
int lineNo=0; // New Variable for Line Number (Can Use variable 'i' also)
for(int i = 0; i < 5; i++) {
lineNo++;
for(int j = i; j < 5; j++) {
System.out.print(" ");
}
if(lineNo%2!=0){
for(int k = 0; k <= (i*2); k++)
System.out.print('*'); // Will print '*' (or '5') Sequence for Odd Lines - 1st, 3rd, 5th Lines
System.out.println();
}
else
System.out.println();// Will print Blank Line for Even Lines - 2nd and 4th Lines
}
}
}

Try this
for(int i = 0; i < 5; i++) {
for(int j = i; j < 5; j++) {
System.out.print(" ");
}
for(int k = 0; k <= (i*2); k++) {
System.out.print("5"); //Use 5 instaed of * to draw
}
System.out.println();
System.out.println(); //This one will solve your problem
}
Output will be:
5
555
55555
5555555
555555555

I think that you can just enter one more print statement inside the loop:
for(int i = 0; i < 5; i++) {
System.out.println();
for(int j = i; j < 5; j++) {
System.out.print(" ");
}
for(int k = 0; k <= (i*2); k++) {
System.out.print("*");
}
System.out.println();
}
Output
*
***
*****
*******
*********

Cannot get the addition to output [closed]

Closed. This question needs debugging details. It is not currently accepting answers.
Edit the question to include desired behavior, a specific problem or error, and the shortest code necessary to reproduce the problem. This will help others answer the question.
Closed 8 years ago.
Improve this question
Everything is good, but i just cant get the addition to show up? When I run the program it is blank when it comes to the addition of the matrixes part. Thanks in advance. BtW does anyone know how I would make this display right column justified?
public static void displayMatrixes(int[][] matrix1, int[][] matrix2, int[][] resultsMatrix) {
System.out.println("This is how i want it to output");
for (int i = 0; i < 3; i++) {
for (int j = 0; j < 3; j++) {
System.out.print(matrix1[i][j] + " ");
}
System.out.print("+ ");
for (int j = 0; j < 3; j++) {
System.out.print(matrix2[i][j]+ " ");
}
System.out.print("= ");
for (int j = 0; j < 3; j++) {
System.out.print(resultsMatrix[i][j]+ " ");
}
System.out.println();
}
)
This is my code
import java.util.Scanner;
public class MatrixAdd
{
public static void main(String arg[])
{
Scanner input = new Scanner(System.in);
int a[][]= new int[3][3];
int b[][] = new int[3][3];
int row, column;
System.out.println("\nEnter Matrix A: \n");
for (int i = 0 ; i < 3 ; i++){
for (int j = 0; j<3 ; j++){
a[i][j] = input.nextInt();
}
}
System.out.println("\nEnter Matrix B: \n");
for (int i = 0; i < 3; i++){
for (int j = 0; j < 3; j++){
b[i][j] = input.nextInt();
}
}
System.out.println("\nMatrix A + Matrix B = Matrix C: \n");
int[][] resultingMatrix = addMatrix(a, b);
}
public static int[][] addMatrix(int[][] a, int[][] b){
int[][] result = new int[a.length][a[0].length];
for (int i = 0; i < result.length; i++) {
for (int j = 0; j < result[0].length; j++){
result[i][j]=a[i][j] + b[i][j];
}
}
for (int i = 0; i < a.length; i++) {
char plus = '+';
for (int j = 0; j < a[0].length; j++) {
System.out.print(" " + a[i][j]);
}
if (i == a.length / 2)
System.out.print(" " + plus + " ");
else {
System.out.print(" ");
}
for (int j = 0; j < b[0].length; j++) {
System.out.print(" " + b[i][j]);
}
if (i == a.length / 2)
System.out.print(" = ");
else {
System.out.print(" ");
}
for (int j = 0; j < result[0].length; j++) {
System.out.print(" " + " " + result[i][j]);
}
System.out.println();
}
return result;
}//end of add matrices
}//end of class

I doubt that the given program compiles. In this line: int[][] resultsMatrix = displayMatrixes(a, b); you are expecting an int[][], but in your method displayMatrixes you are not returning anything. You are also expecting a 3rd parameter which you are not passing.
Also, the displayMatrixes method has no return value, which since you are returning something at the end, you must have. Try it again like so:
public static void main(String arg[]) {
Scanner input = new Scanner(System.in);
int a[][] = new int[3][3];
int b[][] = new int[3][3];
int row, column;
System.out.println("\nEnter Matrix A: \n");
for (int i = 0; i < 3; i++) {
for (int j = 0; j < 3; j++) {
a[i][j] = input.nextInt();
}
}
System.out.println("\nEnter Matrix B: \n");
for (int i = 0; i < 3; i++) {
for (int j = 0; j < 3; j++) {
b[i][j] = input.nextInt();
}
}
System.out.println("\nMatrix A + Matrix B = Matrix C: \n");
displayMatrixes(a, b);
}
public static void displayMatrixes(int[][] a, int[][] b) {
for (int i = 0; i < 3; i++) {
for (int j = 0; j < 3; j++) {
System.out.print(a[i][j] + " ");
}
System.out.print("+ ");
for (int j = 0; j < 3; j++) {
System.out.print(b[i][j] + " ");
}
System.out.print("= ");
for (int j = 0; j < 3; j++) {
System.out.print((a[i][j] + b[i][j]) + " ");
}
System.out.println();
}
}
}

printf with The "%3d" specifier means a minimum width of three spaces, which, by default, will be right-justified.
for your right alignment question you can at http://alvinalexander.com/programming/printf-format-cheat-sheet