Java if else & switch Practice Questions

Below are few questions on Java if else and switch

1. Convert the following if-else-if construct into switch case:

if(var == 1)
System.out.println("good");
else if(var == 2)
System.out.println("better");
else if(var == 3)
System.out.println("best");
else
System.out.println("invalid");

Ans

switch(var) {
case 1:
System.out.println("good");
break;
case 2:
System.out.println("better");
break;
case 3:
System.out.println("best");
break;
default:
System.out.println("invalid");
}

2. Find the output in the following code snippet:

int ch=2;
switch(ch) {
case 1: System.out.println("All courses");
Break;
case 2: System.out.println("Simply Coding ");
case 3: System.out.println("Best Study Material");
}

Ans.

Simply Coding
Best Study Material

3. Rewrite the following program code using suitable ‘if’ command.

switch(m){
case 0:
 x=x+2;
 System.out.println(“X=” x);
 break;
case 1:
 x=x+4;
 System.out.println(“X=” x);
 break;
case 2:
 x=x+6;
 System.out.println(“X=” x);
 break; }

Ans:

if(m==0){
x= x+2;
System.out.println(“X=” +x);
}
else if(m==1){
x= x+4;
System.out.println(“X=” +x);
}
if(m==2){
x= x+6;
System.out.println(“X=” +x);
}

4. What is wrong in the following program code? Find any 2 errors and explain.

switch (p)
?
case 3:
 int x= 12; int y = 35;
 int z= x* y;
 break;
case 3:
 int a = 20;
 int b = 76;
 break;
 int z=x * y;

Ans.

• Just after switch statement the question mark (?) symbol should be replaced by open brace (), this shows the beginning of switch block.
• The constants value for two or more case statements cannot be same so, one should be changed.
• In case 3 the break statement is present before the last statement z= x* y which is wrong and the error message that appears is “unreachable code”.

5. Rewrite the following code after corrections.

int a;
if(a=1)
 a==100;
else If(a=2)
 a=1000;

Ans:

int a;
if(a==1)
a=100;
else if(a==2)
a=1000;

6. Give the output of the following code fragment when

(i) opn = ‘b’
(ii) opn = ‘x’

switch (opn)
{
case ‘a’:
System.out.println(“Simply Coding”);
break;
case ‘b’:
System.out.println(“Online Tutor”);
case ‘c’:
System.out.println(“Online Courses”);
default:
System.out.println(“Invalid Input”);
}

Ans.

i.    Online Tutor

     Online Courses

     Invalid Input

ii.  Invalid Input