Type casting in Java - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to convert an integer to a double.

Java

int num = 5;
double result = ([1]) num;
System.out.println(result);

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Afloat

Bint

Cdouble

Dlong

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong type in the cast, like int or float.

Forgetting the parentheses around the type.

We use (double) to cast an integer to a double type in Java.

2fill in blank

medium

Complete the code to cast a double to an integer.

Java

double pi = 3.14;
int whole = ([1]) pi;
System.out.println(whole);

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Adouble

Bint

Cfloat

Dlong

Attempts:

3 left

💡 Hint

Common Mistakes

Using (double) instead of (int).

Expecting rounding instead of truncation.

To convert a double to an int, use (int) cast. This drops the decimal part.

3fill in blank

hard

Fix the error in casting a long to an int.

Java

long bigNumber = 100000L;
int smaller = ([1]) bigNumber;
System.out.println(smaller);

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Along

Bfloat

Cdouble

Dint

Attempts:

3 left

💡 Hint

Common Mistakes

Casting to the same type (long) instead of int.

Forgetting to cast and causing a compile error.

To cast a long to an int, use (int). Casting to long again is incorrect.

4fill in blank

hard

Fill both blanks to create a dictionary with string keys and integer values using casting.

Java

Map<String, Integer> map = new HashMap<>();
String key = "age";
Object value = 30;
map.put(key, ([1]) value);
int age = ([2]) map.get(key);
System.out.println(age);

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AInteger

BString

Cint

DDouble

Attempts:

3 left

💡 Hint

Common Mistakes

Casting to String instead of Integer.

Casting to Double which is incompatible.

Using int instead of Integer when putting into the map.

Cast value to Integer when putting in the map, and cast the retrieved value to int when getting it.

5fill in blank

hard

Fill all three blanks to cast and calculate the average of two numbers.

Java

int a = 5;
int b = 8;
double average = (([1]) a + ([2]) b) / [3];
System.out.println(average);

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Adouble

C2.0

Dint

Attempts:

3 left

💡 Hint

Common Mistakes

Dividing by integer 2 causing integer division.

Not casting both numbers to double.

Casting to int which does not help here.

Cast a and b to double to avoid integer division, then divide by 2.0 to get a double average.