程序中输入 3 位数字并检查哪些数字是偶数并将其替换为奇数的问题

Question

Problem while entering a 3 digit no and getting no result. after entering 123 and when 2 is detected as even, and if user enters 7, it should display 173. but the program is immediately ending. It might be a problem in the last 0 check if-block. but removing it also doesn't help. Thanks in advance!

// in 3 dig, check even dig., replace them with odd and disp.
import java.util.*;
public class p24123 {
    public static void main(String[] args) {
        int n,h,t,o,m,z=0,z1=0,z2=0,fn;
        Scanner ob = new Scanner(System.in);
        n=ob.nextInt();
        if(n>99&&n<1000){
            h= n/100;
            o=n%10;
            m=n/10;
            t=m%10;
            if(h%2==0){
               z=h;
                System.out.println("Enter the odd number you would like to replace the EVEN hundred's digit"+h+" with \n");
                z=ob.nextInt();
                if(z%2==0){
                    System.out.println("That's not odd. So we will keep the original digit in it's place");
                    z=h;
                }
                else if(t%2==0) {
                    System.out.println("Condition enter bokachpda");
                    z1 = t;
                    System.out.println("Enter the odd number you would like to replace the EVEN ten's digit" + t + " with \n");
                    z1 = ob.nextInt();
                    if (z % 2 == 0) {
                        System.out.println("That's not odd. So we will keep the original digit in it's place");
                        z1 = t;
                    }
                }
                else if(o%2==0){
                    z2=o;
                    System.out.println("Enter the odd number you would like to replace the EVEN one's digit"+h+" with \n");
                    z2=ob.nextInt();
                    if(z2%2==0){
                        System.out.println("That's not odd. So we will keep the original digit in it's place");
                        z2=o;
                    }
                }
                else if(2==2){
                    if(h<1||t<1||o<1||z<1||z1<1||z2<1){
                        System.out.println("Error");
                        System.exit(0);

                    }
                }
                fn=z*100+z1*10+z;


            }
        }
    }

}

Answer 1

Here's your code cleaned up and fixed. I modified as little as possible to keep it at a level a beginner would be comfortable with. Some improvements to be made:

• Repeated code like this screams, "Put me in my own function!"
• A loop can be used to handle any number of digits, not just three.
• Error checking/handling. You should handle bad input. What if the user enters "hello" instead of a number?

Improvements I made:

• Your original code never printed a result.
• Better formatting. It makes the code easier to read.
• Descriptive variable names!

Scanner ob = new Scanner(System.in);
int n = ob.nextInt();
if (n > 99 && n < 1000) {
    int hundredsDigit = n / 100;
    int tensDigit = n / 10 % 10;
    int onesDigit = n % 10;
    
    if (hundredsDigit % 2 == 0) {
        System.out.println("Enter the odd number you would like to replace the EVEN hundred's digit " + hundredsDigit +" with \n");
        int replacementDigit = ob.nextInt();
        if (replacementDigit % 2 == 0) {
            System.out.println("That's not odd. So we will keep the original digit in it's place");
        }
        else {
            hundredsDigit = replacementDigit;
        }
    }
    if (tensDigit % 2 == 0) {
        System.out.println("Enter the odd number you would like to replace the EVEN ten's digit " + tensDigit + " with \n");
        int replacementDigit = ob.nextInt();
        if (replacementDigit % 2 == 0) {
            System.out.println("That's not odd. So we will keep the original digit in it's place");
        }
        else {
            tensDigit = replacementDigit;
        }
    }
    if (onesDigit % 2 == 0) {
        System.out.println("Enter the odd number you would like to replace the EVEN one's digit " + onesDigit + " with \n");
        int replacementDigit = ob.nextInt();
        if (replacementDigit % 2 == 0) {
            System.out.println("That's not odd. So we will keep the original digit in it's place");
        }
        else {
            onesDigit = replacementDigit;
        }
    }
    System.out.println(hundredsDigit * 100 + tensDigit * 10 + onesDigit);
}