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Computers can represent only a finite number of digits. It is therefore impossible to precisely represent repeating binary -representation valuessequences of floating point numbers. This includes many finite decimal numbers, such as 1/10.

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Noncompliant Code Example

This very simple example attempts to do noncompliant code example performs some basic currency calculations:.

double dollar = 1.0;

double dime = 0.1;

int number = 7;

System.out.println ("A dollar less " + number + " dimes is $" +
		    (dollar - number*dime) );

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A dollar less 7 dimes is $0.29999999999999993

Compliant Solution

A better approach is to use This compliant solution uses an integer type (such as long) and work works in cents rather than dollars.

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A dollar less 7 dimes is 30 cents

Compliant Solution

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An alternative approach is to use the BigDecimal type, though it is less efficient performance wise.

Code Block
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import java.math.BigDecimal; // ... BigDecimal dollar = new BigDecimal("1.0"); BigDecimal dime = new BigDecimal("0.1"); int number = 7; System.out.println ("A dollar less " + number + " dimes is $" + (dollar.subtract( new BigDecimal(number).multiply(dime) )) );

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