Non-terminating decimal expansion; no exact representable decimal result 两个double 类型相除 java

Non-terminating decimal expansion refers to a situation where the decimal representation of a mathematical fraction, when expressed as a floating-point number, does not have an exact representation in binary format used by computers. This occurs when the division of two numbers results in a non-terminating or recurring decimal pattern that cannot be represented precisely with the finite precision of a double data type, which has a limited number of bits for storing fractional parts.

In Java, specifically with the `double` type, this happens because the IEEE 754 standard used for floating-point arithmetic reserves some bits for the exponent and mantissa, leading to a finite set of possible values. When dividing two `double` numbers with an exact ratio that cannot be expressed as a simple fraction with integer coefficients, the result will be approximated based on these limitations.

For example, consider the division of 1 by 3 in decimal form, which is an infinite repeating decimal (0.3333...). If you try to store this value in a `double`, you will get an approximation like 0.3333333333333333, and if you perform calculations involving this number repeatedly, the sequence may start to diverge slightly due to rounding errors.

When such a case arises, it's important to handle the potential for inaccuracies in your code. You can use libraries like BigDecimal for more precise decimal arithmetic or implement custom algorithms to manage the precision issues.