Home / Questions / Question: Given the following code fragment: if (a == 0) System.out.println("Zero"); if (a == 1) System.out.println("One"); if (a == 2) System.out.println("Two"); if (a == 3) System.out.println("Three"); Write an alternative code (using if) that saves on the number of comparisons.
Explanatory Question

Question:

Given the following code fragment:

if (a == 0) System.out.println("Zero");
if (a == 1) System.out.println("One");
if (a == 2) System.out.println("Two");
if (a == 3) System.out.println("Three");

Write an alternative code (using if) that saves on the number of comparisons.

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Answer with Explanation

Question:

Given the following code fragment:

if (a == 0) System.out.println("Zero");
if (a == 1) System.out.println("One");
if (a == 2) System.out.println("Two");
if (a == 3) System.out.println("Three");

Write an alternative code (using if) that saves on the number of comparisons.

Answer:

The given code performs four separate comparisons, even if one condition is already true.
We can reduce the number of comparisons by using an if–else if ladder, so that once a condition is true, the rest are skipped.

if (a == 0)
    System.out.println("Zero");
else if (a == 1)
    System.out.println("One");
else if (a == 2)
    System.out.println("Two");
else if (a == 3)
    System.out.println("Three");

Explanation:

  • In the original code, all four if conditions are checked independently.

  • In the improved version, if one condition is true, the remaining else if conditions are not evaluated.

  • This approach reduces the number of comparisons and makes the program more efficient.

✅ Final Answer:

if (a == 0)
    System.out.println("Zero");
else if (a == 1)
    System.out.println("One");
else if (a == 2)
    System.out.println("Two");
else if (a == 3)
    System.out.println("Three");