My code is for a java 101 course and it works fine until the while loop. I put in the last input for the t, c, r, q options but it always goes to the else option where it shows "invalid input". The if statements just don't catch the 'answer' variable and always goes to the else statement.
import java.util.Scanner;
public class homework { public static void main(String[] args) {
Scanner input = new Scanner (System.in);
System.out.printf ("Enter number of rows: ");
int rows = input.nextInt();
Scanner input2 = new Scanner (System.in);
System.out.printf ("Enter number of columns: ");
int column = input2.nextInt();
int[][] array = new int[rows][column];
for (int i =0; i < rows ; i++) {
for(int j = 0; j < column; j++) {
array[i][j] = (i*10)+j;
System.out.printf("%4d", array[i][j]);
}
System.out.println();
}
System.out.printf("T transpose - Rows become columns (and vice versa)%n");
System.out.printf("C columnSum - Calculate the sum of the values in each column%n");
System.out.printf("R reverseRows - Reverse all elements in every row of the matrix%n");
System.out.printf("Q quit - Exit the program%n");
boolean isValid = true;
while (isValid) {
Scanner input3 = new Scanner (System.in);
String answer = input3.next().toLowerCase();
if (answer == "t") {
for (int i =0; i < rows ; i++) {
for(int j = 0; j < column; j++) {
array[i][j] = (j*10)+i;
System.out.printf("%4d", array[i][j]);
}
System.out.println();
}
isValid = false;
}
if (answer == "c") {
}
if (answer == "r") {
}
if (answer == "q") {
System.out.println("Goodbye");
isValid = false;
}
else {
System.out.println("Invalid input, please try again...");
isValid = true;
}
}
}
}
