boolean HW

FRQ

a)

public static int numberOfLeapYears(int year1, int year2) {
    int cnt = 0;
    for (int y=year1; y<=year2; y++) {
        if (isLeapYear(y)) {
            cnt++;
        }
    }
    return cnt; 
}

b)

public static int dayOfWeek(int month, int day, int year) {
    int firstDay = firstDayOfYear(year);
    int doy = dayOfYear(month, day, year);
    return (firstDay + doy - 1) % 7;
}

Conditional Exercises

2

public class main {

    
  public static void main(String[] Strings) {

            double a = 1;
            double b = 3;
            double c = 2;

            double result = b * b - 4.0 * a * c;

            if (result > 0.0) {
                double r1 = (-b + Math.pow(result, 0.5)) / (2.0 * a);
                double r2 = (-b - Math.pow(result, 0.5)) / (2.0 * a);
                System.out.println("The roots are " + r1 + " and " + r2);
            } else if (result == 0.0) {
                double r1 = -b / (2.0 * a);
                System.out.println("The root is " + r1);
            } else {
                System.out.println("The equation has no real roots.");
            }

    }
}
main.main(null)

The roots are -1.0 and -2.0

4

public class main {

    
    public static void main(String[] Strings) {
  
              double a = 1;
            
  
              if (a > 0.0) {
                  System.out.println("positive number");
              } else {
                  System.out.println("negative number");
              }
  
      }
  }
  main.main(null)

positive number

6

public class main {

    
    public static void main(String[] Strings) {
  
              double a = 55.1321;
              double b = 55.132;

              a = Math.round(a * 1000);
              b = Math.round(b * 1000);
            
  
              if (a == b) {
                  System.out.println("same");
              } else {
                  System.out.println("different");
              }
  
      }
  }
  main.main(null)

same

8

public class main {

    
    public static void main(String[] Strings) {
  
        String a = "a";
            
        boolean vowels = a.equals("a") || a.equals("e") || a.equals("i") || a.equals("o") || a.equals("u");
              

        if (a.length() > 1)
        {
            System.out.println("not one letter");
        }
        else if (vowels)
        {
            System.out.println("vowel");
        }
        else
        {
            System.out.println("consonant");
        }
    }
}
  main.main(null)

vowel

10

public class main {
    
    public static void main(String[] args) {
           
      int i;
      for (i=1;i<=10;i++) {      
          System.out.println (i);
      }
    }
}
main.main(null)

1
2
3
4
5
6
7
8
9
10

12

public class main {
    
    public static void main(String[] args) {
        int a = 3;
        int b = 4;
        int c = 1;
        int d = 7;
        int e = 3;

        double sum = a + b + c + d + e;
        double avg = sum/5; 
        System.out.println(sum);
        System.out.println(avg);
    }
}
main.main(null)

18.0
3.6

14

public class main {
    
    public static void main(String[] args) {
        int a = 4;
        int b = 3;
        int i;
        for(i = 0; i <= b; i++) {
            int c = a * i;
            System.out.println(a + " * " + i + " = " + c);
            c = 0;
        }
    }
}
main.main(null)

4 * 0 = 0
4 * 1 = 4
4 * 2 = 8
4 * 3 = 12

16

public class main {

    public static void main(String[] args) {
    int a;
    int b;
    int r = 5;
 
    for(a=1;a<=r;a++) {
     for(b=1;b<=a;b++)
       System.out.print(b);
 
     System.out.println("");
     }
 }
}
main.main(null);

1
12
123
1234
12345

18

public class main {

    public static void main(String[] args) {
        int a,b,c=1;
        int n = 4;
        for(a=1;a<=n;a++)
        {
        for(b=1;b<=a;b++)
        System.out.print(c++);
        System.out.println(" ");
        }
    }
}
main.main(null);

1
23
456
78910

20

public class main {

    public static void main(String[] args) {
        int a,b,c=1;
        int n = 5;
        for(a=1;a<=n;a++)
        {
        for(b=1;b<=a;b++)
        System.out.print(" " + c++);
        System.out.println(" ");
        }
    }
}
main.main(null);

 1 
 2 3 
 4 5 6 
 7 8 9 10 
 11 12 13 14 15 

String[] names = new String[] {"samuel", "kian", "samuel", "bob"};

for(int i = 0; i < names.length; i++ ) {
    for(int j = 0; j < names.length; j++) {
        if(names[i]==names[j]) {
            System.out.println(names[j]);
        }
    } 
}

samuel
samuel
kian
samuel
samuel
bob