Practice Questions: Code Segments

1. String s1 = new String("TODAY");
   String s2 = s1.substring(2, 4);
   

   What is the value of s2?

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2. String s3 = new String("TOMORROW");
   s3.replace('O', '*');
   s3.replace('R', '#');
   

   What is the value of s3?

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3. String s4 = new String("TOMORROW");
   String s5 = new String("YESTERDAY");
   

   What is the value of s4.compareTo(s5) > 0?

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4. What is printed by the following code fragment?

   for(int k = 0;  k < 2;  k = k + 1)
   {
     for(int j = 3;  j > 1;  j = j - 1)
     {
       System.out.print(j);
     }
   }
   

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5. What is the printed by the following code?

   int[] value = {1, 2, 8, 3, -1, -2, 4};
   int sum = 0; 
   for (int k = 1; k < value.length; k += 2) 
   {
       sum = sum + value[k - 1];
   }
   System.out.println(sum);
   

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6. Consider the following method.

   public int isOK(int[] data)
   {   int k = 1;
       while (k < data.length) 
       {
           if (data[k-1] > data[k]) 
               return k;
           k++;
       }
       return -1;
   }
   

   Now consider the following code segment.

   int[] array1 = {2, 4, 7, 11, 15, 15};
   int hasProperty = isOK(array1);
   

   What is the value of hasProperty?

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7. What is printed by the following code fragment?

   String s = "Pittsburgh";
   int index = 0;
   while(s.charAt(index) != 't')
   {
     index++;
     System.out.print(s.charAt(index));
   }
   

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8. What is printed by the following code fragment?

   String s6 = "Today";
   for(int p = 0;  p  <  5;  p++){
     if(s6.charAt(p) > 'm')
       System.out.print('#');
     else
       System.out.print('*');
   }
   

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9. What is printed by the following code fragment?

   int x = 23;
   int y = 33;
   int z = 10;
   if(z >= x  ||  z < y){
     if(x != y  &&  x <= z)
       System.out.print("HIGH");
     else
       System.out.print("LOW");
   }
   else
     System.out.print("MIDDLE");
   

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10. Consider the following code segment.

    int k = 12345;
    int digit = (((k % 1000) - (k % 100))/100);
    

    What is the value of digit?

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11. What is printed by the following code segment?

    int[] values = {5, 4, 3, 2, 1};
    for (int i = 4; i > 0; i--)
      values[i - 1] = values[i];
    for (int i = 0; i < 5; i++)
      System.out.println(values[i]);
    

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12. What is printed by the following code segment?

    for (int i = 2; i < 20; i += 3)
      if (i % 4 == 1)
        System.out.println(i);
    

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13. What is printed by the following code segment?

    int[] x = new int[7];
    int index = 0;
    for (int i = 100; i > 0; i = i / 2)
    {
      x[index] = i;
      index++;
    }
    for (int i = 0; i < x.length; i++)
      System.out.println(x[i]);
    

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14. What is printed by the following code segment?

    int[] next = {3, 5, 0, -1, 5, 7, 0, 6};
    int i = 1;
    while (i >= 0)
    {
      System.out.println(i);
      i = next[i];
    }
    

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15. Consider the following method:

    public static void mystery(int[] a, int[] b, String s)
    {
      a = b;
      a[0] = a[0] + 1;
      s = "a[0]";
    }
    

    What is printed by the following code segment?

    int[] a = {3};
    int[] b = {7};
    String s = "hello";
    mystery(a, b, s);
    System.out.println(a[0]);
    System.out.println(b[0]);
    System.out.println(s);