如何在Go中添加两个任意大数？

Question

When I add two very large floats I get the wrong output. How can I do this in Go? PHP has the bcadd function.

var a float64 = 12959653081233191386469183112744623843489338314724603559902557916087872259523073406440221030943397504960564327459290759156915189196536625503825265749393408
var b float64 = 1302494993937727547864388263735304125561725318351673964024430436931705604299209078600534362879064309484886438718428990856894006118477463552
// correct value: 12959653081233192688964177050472171707877602050028729121627876267761836283953510338145825330152476105494927206523600244043353907625527482397831384226856960
// actual output: 12959653081233192875034890470147535688504496869357889916160064603715259716015001328389483087182344476999836189247073027598559438829669033382689401152208896
fmt.Println(strconv.FormatFloat(a+b, 'f', 0, 64))

Answer 1

who can help me? in php has bcadd function

bcadd and its friends are arbitrary precision arithmetic functions (that's why they operate on strings and not floats). A float has limited precision. In effect, bcmath offers infinitely more precision than a float.

Use math/big.