97 lines
2.0 KiB
Plaintext
97 lines
2.0 KiB
Plaintext
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/*
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* 判断obj是否为一个整数
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*/
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function isInteger(obj) {
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return Math.floor(obj) === obj
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}
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/*
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* 将一个浮点数转成整数，返回整数和倍数
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* @param floatNum {number} 小数
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* @return {object}
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* {times:100, num: 314}
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*/
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function toInteger(floatNum) {
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var ret = { times: 1, num: 0 }
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if (isInteger(floatNum)) {
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ret.num = floatNum
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return ret
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}
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var strfi = floatNum + ''
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var dotPos = strfi.indexOf('.')
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var len = strfi.substr(dotPos + 1).length
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var times = Math.pow(10, len)
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var intNum = parseInt(floatNum * times + 0.5, 10)
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ret.times = times
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ret.num = intNum
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return ret
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}
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/*
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*
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* @param a {number} 运算数1
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* @param b {number} 运算数2
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* @param op {string} 运算类型，有加减乘除
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*
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*/
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function operation(a, b, op) {
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var o1 = toInteger(a)
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var o2 = toInteger(b)
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var n1 = o1.num
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var n2 = o2.num
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var t1 = o1.times
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var t2 = o2.times
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var max = t1 > t2 ? t1 : t2
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var result = null
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switch (op) {
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case 'add':
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if (t1 === t2) { // 两个小数位数相同
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result = n1 + n2
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} else if (t1 > t2) { // o1 小数位 大于 o2
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result = n1 + n2 * (t1 / t2)
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} else { // o1 小数位 小于 o2
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result = n1 * (t2 / t1) + n2
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}
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return result / max
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case 'subtract':
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if (t1 === t2) {
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result = n1 - n2
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} else if (t1 > t2) {
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result = n1 - n2 * (t1 / t2)
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} else {
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result = n1 * (t2 / t1) - n2
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}
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return result / max
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case 'multiply':
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result = (n1 * n2) / (t1 * t2)
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return result
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case 'divide':
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result = (n1 / n2) * (t2 / t1)
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return result
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}
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}
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function add(a, b) {
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return operation(a, b, 'add')
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}
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function subtract(a, b) {
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return operation(a, b, 'subtract')
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}
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function multiply(a, b) {
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return operation(a, b, 'multiply')
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}
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function divide(a, b) {
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return operation(a, b, 'divide')
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}
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export default {
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add: add,
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subtract: subtract,
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multiply: multiply,
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divide: divide
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}
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