One Dimensional Array

A one-dimensional array is a single ordered sequence of values. Java indexes it from 0 through length - 1. Use it for lists such as marks, prices, names, or daily readings.

Read values with an enhanced for loop

Run this example to see its output.

The enhanced for loop gives you each value, but not its index. It is the clearest option when you only need to read values.

Use indexes when position matters

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The condition is index < marks.length, not index <= marks.length. The latter tries to access one position beyond the final element.

Calculate a total and average

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The cast to double prevents integer division. Without it, 311 / 4 would become 77 instead of 77.75.

Find the maximum value

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This requires a non-empty array because it begins with marks[0]. For data that may be empty, check marks.length == 0 first.

What to remember

• Use enhanced for when you only need values.
• Use an indexed for loop when position or updates matter.
• The final valid index is array.length - 1.
• Cast before division when an average needs a decimal result.