# JS floating-point arithmetic appears as decimal

Source: Internet
Author: User
Tags mul pow

/**************************************** solve the error of JS floating point (decimal) calculation subtraction start****************************************/

Problem: JS floating-point arithmetic problem---inexplicable number of decimal places

Cause: This is due to the operation of converting the floating-point number into binary before the operation,
But some decimals have an infinite loop after the binary code,
This results in an error in the calculation and a similar problem in other languages.

/**
* * Description: JavaScript addition results will be error, when the two floating-point number added will be more obvious. This function returns a more accurate addition result.
* * return value: Arg1 plus arg2 accurate results
**/

`functionAccadd (arg1, arg2) {if(IsNaN (arg1)) {arg1= 0; }    if(IsNaN (arg2)) {arg2= 0; } arg1=Number (ARG1); Arg2=Number (ARG2); varR1, R2, M, C; Try{R1= Arg1.tostring (). Split (".") [1].length; }    Catch(e) {R1= 0; }    Try{R2= Arg2.tostring (). Split (".") [1].length; }    Catch(e) {R2= 0; } C= Math.Abs (R1-R2); M= Math.pow (10, Math.max (R1, r2)); if(C > 0) {        varCM = Math.pow (10, c); if(R1 >R2) {Arg1= Number (arg1.tostring (). Replace (".", "")); Arg2= Number (arg2.tostring (). Replace (".", "")) *cm; } Else{arg1= Number (arg1.tostring (). Replace (".", "")) *cm; Arg2= Number (arg2.tostring (). Replace (".", "")); }    } Else{arg1= Number (arg1.tostring (). Replace (".", "")); Arg2= Number (arg2.tostring (). Replace (".", "")); }    return(Arg1 + arg2)/m;}`

Adding an Add method to the number type makes it more convenient to call.

`function (ARG) {    return accadd (this, arg);};`

/**
* * Subtraction function to get accurate subtraction results
* * Description: JavaScript subtraction results will be error, when the two floating-point subtraction will be more obvious. This function returns a more accurate subtraction result.
* * Call: Accsub (ARG1,ARG2)
* * return value: Arg1 plus arg2 accurate results
**/

`functionaccsub (arg1, arg2) {if(IsNaN (arg1)) {arg1= 0; }    if(IsNaN (arg2)) {arg2= 0; } arg1=Number (ARG1); Arg2=Number (ARG2); varR1, R2, M, N; Try{R1= Arg1.tostring (). Split (".") [1].length; }    Catch(e) {R1= 0; }    Try{R2= Arg2.tostring (). Split (".") [1].length; }    Catch(e) {R2= 0; } m= Math.pow (Ten, Math.max (R1, r2));//Last Modify by Deeka//dynamic control accuracy lengthn = (r1 >= r2)?R1:R2; return((ARG1 * M-ARG2 * m)/m). toFixed (n);}`

Adding a Mul method to the number type makes it more convenient to call.

`function (ARG) {    return accsub (this, arg);};`

/**
* * Multiplication function to get accurate multiplication results
* * Note: The multiplication result of JavaScript will be error, it will be more obvious when two floating-point numbers are multiplied. This function returns a more accurate multiplication result.
* * Call: Accmul (ARG1,ARG2)
* * return value: Arg1 times the exact result of arg2
**/

`functionAccmul (arg1, arg2) {if(IsNaN (arg1)) {arg1= 0; }    if(IsNaN (arg2)) {arg2= 0; } arg1=Number (ARG1); Arg2=Number (ARG2); varm = 0, S1 = arg1.tostring (), S2 =arg2.tostring (); Try{m+ = S1.split (".") [1].length; }    Catch(e) {}Try{m+ = S2.split (".") [1].length; }    Catch(e) {}returnNumber (S1.replace (".", "")) * Number (S2.replace (".", ""))/Math.pow (10, M);}`

Adding a Mul method to the number type makes it more convenient to call.

`function (ARG) {    return accmul (this, arg);};`

/**
* * Division function to get accurate division results
* * Description: JavaScript division results will be error, when the two floating point number is more obvious when dividing. This function returns a more accurate division result.
* * Call: Accdiv (ARG1,ARG2)
* * return value: Arg1 divided by the exact result of arg2
**/

`functionAccdiv (arg1, arg2) {if(IsNaN (arg1)) {arg1= 0; }    if(IsNaN (arg2)) {arg2= 0; } arg1=Number (ARG1); Arg2=Number (ARG2); varT1 = 0, t2 = 0, R1, R2; Try{T1= Arg1.tostring (). Split (".") [1].length; }    Catch(e) {}Try{T2= Arg2.tostring (). Split (".") [1].length; }    Catch(e) {} with(Math) {R1= Number (arg1.tostring (). Replace (".", "")); R2= Number (arg2.tostring (). Replace (".", "")); return(R1/R2) * POW (T2-t1); }}`

Adding a Div method to the number type makes it easier to call.

`function (ARG) {    return accdiv (this, arg);};`

/**************************************** solve the error of JS floating point (decimal) calculation subtraction end****************************************/

JS floating-point arithmetic appears as decimal

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