CECS 174                                          QUIZ #3          

 

1. Here is a collection of if and if-else statements with semicolons in various places. Assume all variables
have been declared and initialized. Which of those are correct and are likely to give the programmers intent?
Which are correct but unlikely to give the programmer's intent? Give the error for the remaining.

a) if ( a > b );
   a = b;
   else
   b = a;
b) if ( a > b )
   a = b;
   else;
   b = a;
c) if ( a > b )
   a = b;
   else
   b = a;
d) if (a > b)
   a = b
   else
   b = a;
Answer

a) if ( a > b ); // No semicolon
   a = b;
   else
   b = a;
b) if ( a > b )
   a = b;
   else; //No semicolon
   b = a;
c) if ( a > b ) //Correct
   a = b;
   else
   b = a;
d) if (a > b)
   a = b //Missing semicolon   a = b;
   else
   b = a;

2. Use the coding below to answer the questions a and b.

int x;
if ( x> 10)
  {   x = x + 10;
      System.out.println(x);
  }
else
      System.out.println(x);
System.out.println("Done");

a. What is the output if x is equal to 20?
Answer

30
Done

b. What is the output if x is equal to 5?
Answer
5
Done

3. Use the coding below to answer the questions a and b.

int x;
if ( x> 10)
  {   x = x + 10;
      System.out.println(x);
  }
else
{     x = x + 20;
      System.out.println(x);
}
     
System.out.println("Done");

a. What is the output if x is equal to 20?
Answer

30
Done

b. What is the output if x is equal to 5?
Answer
25
Done

4.  Use the coding below to answer the questions a and b.

int x;
if ( x> 10)
  {   System.out.println("A");
      System.out.println("B");
  }          
     System.out.println("Done");

a. What is the output if x is equal to 20?
Answer
A
B
Done

b. What is the output if x is equal to 5?
Answer
Done

5.  Use the coding below to answer the questions a and b.

int x;
if ( x> 10)
     System.out.println("A");
      System.out.println("B");            
     System.out.println("Done");

a. What is the output if x is equal to 20?
Answer
A
B
Done

b. What is the output if x is equal to 5?
Answer
B
Done            

6. What is the output of the following C++ code?

 

     x = 6;

     if (x > 10)
       System.out.println("Two");
       System.out.printl("One");

   
     Answer
     One
 

7. What is the output of the code fragment below?
                     int x =1, y =4;
                    if ( x >=2)
                           x = 7;
                    y = 9;
                System.out.println(x + "*" + y);

             Answer     1 * 9

8. Write a Java statements that will 

    a.     print x>y if x is greater than y and print y>=x otherwise.

   Answer:    if (x > y)
                        System.out.println("x>y");
                    else
                        System.out.println("y>=y");

9. Convert the following while loop to a for loop:

int count = 0;
while(count++ < 50)
{System.out.println("A");
}

Answer    

for(int count = 0; count <50; count++)
              System.out.println("A");

10. Write a for loop that display the following set of numbers:

0, 10, 20, 30, 40, 50 .  .  .  1000,

Answer:

for(int i=0; i <=1000;i = i + 10 )

       {         System.out.print ( i + ",");                 

             }
 11. Write a for  loop while x is greater than 10, each time decreasing x by 2.

   Answer:    while(x > 10)
                      {   x - = 2; }

12. Write a program segment that adds up the even integers from 16 through 2000, inclusive.
Answer:

int sum =0 , evenint = 16;
while ( evenint < = 2000)
{  sum  + = evenint;
   eventint + = 2;
}

13. What is the output of the following code?

int i = 10;
while (i > 0)
  System.out.println("A");
  i = i -2;

Answer
Display many "A"
infinity loop