Decimal Place Carry Cascade Count Tool

Description

Increment a nonnegative decimal digit string while retaining its minimum width and counting trailing-nine carries.

Decimal rounding and scale alignment depend on retained places, discarded digits, tie rules, and the number of rounding stages. A decimal spacing is different from the binary floating-point spacing of a runtime number. Text-based digit operations can preserve widths that disappear when a value is parsed numerically.

Increment a nonnegative decimal digit string while retaining its minimum width and counting trailing-nine carries.

When to use this tool

Use Decimal Place Carry Cascade Count when you need this specific decimal tie, scale, digit-carry, spacing, or staged-rounding check.

How to use the tool and how it works

Enter digits. Use the units and conventions below.
Run the tool. Correct any format, range, or cross-field input error before interpreting the output.
Read incremented, carriedDigits. Use the output convention below.

Require a nonempty string of decimal digits. Count consecutive trailing 9 digits, increment the string's exact integer value by one, and left-pad with zeros to at least the original width; return incremented and carriedDigits.^[1]

Input field	Meaning and units	Accepted input
digits	Digits	Required. Text; maximum UTF-16 length 8192.

Output field	Interpretation	Returned shape
incremented	Incremented	Required. Text; maximum UTF-16 length 8192.
carriedDigits	Count of trailing nines crossed by a unit increment.	Required. Safe integer.

json

{
  "input": {
    "digits": "00999"
  },
  "output": {
    "incremented": "01000",
    "carriedDigits": 3
  }
}

Limitations and assumptions

Leading zeros are preserved up to the original width and an all-nine input grows by one digit. The count describes a unit increment, not an arbitrary addition; extremely long outputs can exceed the declared string bound.
Inputs must satisfy both the field types and the cross-field conditions above. Invalid input causes an error; a successful false flag or documented placeholder is a different result.

Alternative or Complementary methods

Use an exact decimal representation when binary floating-point rounding is inadequate. Apply a complete rounding rule rather than treating a tie-only flag or digit-count term as the whole decision.

References

Calculation and input contract: number/decimal-place-carry-cascade-count — tool.io

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