Grade-Point-Average

---

Download Source Code

Double vs Int

In Java, any number written without a decimal point is assumed to be an integer (int) value.
As soon as there is a decimal point written, the number is a floating point (float) value.
Usually a double value is better than an int value, because:

• double values can be larger, up to 10³⁰⁰
  
• double can have decimals, and will allow correct division operations
• int has values between -2,000,000,000 and +2,000,000,000 (approximately)
  larger values cause an overflow
• int variables cannot store fractions (decimals)

Practice

1. Calculate the average of the following ages:
     25 students are 15 years old
     45 students are 16 years old
     30 students are 17 years old
2. Add up the following:
     1+3
     1+3+5
     1+3+5+7
     ...
     1+3+5+7+....+97+99
   Is there a pattern?
3. Explain why adding up int values gives correct answers,
   but dividing int values gives incorrect answers.