From 5aa28cc827187db0aaeb0936c22e36c9ed37c7da Mon Sep 17 00:00:00 2001
From: yurui wu <wuyurui@glossytech.cn>
Date: Sun, 21 Aug 2022 19:44:45 +0800
Subject: [PATCH] =?UTF-8?q?dev|execise2=E4=BD=9C=E4=B8=9A?=
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---
 lib/add.js | 34 ++++++++++++++++++++++++++++++++--
 1 file changed, 32 insertions(+), 2 deletions(-)

diff --git a/lib/add.js b/lib/add.js
index 1714b95..67ef911 100644
--- a/lib/add.js
+++ b/lib/add.js
@@ -1,5 +1,35 @@
-function add() {
-  // 实现该函数
+function add(strOne, strTwo) {
+    // 比较两个数长度  短的一方前面补0
+    if (strOne.length > strTwo.length) {
+        let arr = Array(strOne.length - strTwo.length).fill(0);
+        strTwo = arr.join('') + strTwo
+    } else if (strOne.length < strTwo.length) {
+        let arr = Array(strTwo.length - strOne.length).fill(0);
+        strOne = arr.join('') + strOne
+    }
+    // 字符串转为数组后反转，方便对数组加法运算
+    var strOneArr = strOne.split('').reverse()
+    var strTwoArr = strTwo.split('').reverse()
+    var sign = 0 // 进位标识
+    var resultArr = []
+
+    for (let i = 0; i < strOneArr.length; i++) {
+        var addResult = Number(strOneArr[i]) + Number(strTwoArr[i]) + sign
+        if (addResult >= 10) {
+            sign = 1
+            resultArr.push(addResult % 10)
+            continue
+        } else {
+            sign = 0
+            resultArr.push(addResult)
+            continue
+        }
+    }
+    // 最后一位计算完后，有进位，计入进位
+    if (sign) {
+        resultArr.push(sign)
+    }
+    return resultArr.reverse().join('')
 }
 
 module.exports = add
\ No newline at end of file