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March 28, 2017 17:12
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rational
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| class Rational { | |
| readonly number: number | |
| readonly denom: number | |
| // -------------- public ---------- | |
| constructor(n: number, d: number){ | |
| this.number = n | |
| this.denom = d | |
| } | |
| add(that): Rational{ | |
| return this._translate(that, (this_n, this_d, that_n, that_d)=>{ | |
| const n = this_n * that_d + that_n * this_d | |
| const d = this_d * that_d | |
| return {n, d} | |
| }); | |
| } | |
| sub(that): Rational { | |
| return this._translate(that, (this_n, this_d, that_n, that_d)=>{ | |
| const n = this_n * that_d - that_n * this_d | |
| const d = this_d * that_d | |
| return {n, d} | |
| }); | |
| } | |
| mul(that): Rational { | |
| return this._translate(that, (this_n, this_d, that_n, that_d)=>{ | |
| const n = this_n * that_n | |
| const d = this_d * that_d | |
| return {n, d} | |
| }); | |
| } | |
| div(that): Rational { | |
| return this._translate(that, (this_n, this_d, that_n, that_d)=>{ | |
| const n = this_n * that_d | |
| const d = this_d * that_n | |
| return {n, d} | |
| }); | |
| } | |
| toFloat(){ | |
| return this.number / this.denom | |
| } | |
| // --------------- static ------------ | |
| static of(n): Rational { | |
| if(n instanceof Rational) { | |
| return n; | |
| } | |
| if(typeof n === 'string'){ | |
| n = parseFloat(n) | |
| } | |
| if(typeof n !== "number"){ | |
| throw new Error("invalidate number") | |
| } | |
| const num = n.toPrecision() | |
| const parts = num.split('.') | |
| var denom = 1 | |
| if(parts.length > 1){ | |
| denom = Math.pow(10, parts[1].length) | |
| } | |
| var number = n * denom | |
| return new Rational(number, denom) | |
| } | |
| // private // | |
| private _translate(_that ,fn: (n:number, d:number, that_n:number, that_d:number)=>{n:number, d:number}) { | |
| var that = _that | |
| if(!(that instanceof Rational)){ | |
| that = Rational.of(that) | |
| } | |
| const this_n = this.number, | |
| this_d = this.denom, | |
| that_n = that.number, | |
| that_d = that.denom; | |
| var r = fn(this_n, this_d, that_n, that_d) | |
| return new Rational(r.n, r.d) | |
| } | |
| } | |
| function safePlus(a, b){ | |
| return Rational.of(a).add(b).toFloat() | |
| } | |
| // console.log(safePlus(1, 2)) | |
| // console.log(safePlus(1.1, 2.1)) | |
| // console.log(safePlus(100000.000001, 100000.000001)) | |
| console.log(1213.11 * 10000) | |
| console.log(safePlus(1213.11, 10000)) |
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