6-1 Array function exercises

1. References

/*          var num = 10;            function show(num){                num++;                alert(num);            }            alert(num); //10            show(num);  //11  num = num            alert(num); //10*/            /*                引用            */            /*var arr = [1, 2, 3, 4];            function show(arr){                arr.push("hello");                alert(arr);            }            alert(arr); //[1, 2, 3, 4]            show(arr);  //[1, 2, 3, 4, "hello"]            alert(arr); //[1, 2, 3, 4, "hello"]*/

2. Reference sort function

3. Return

/*function add(num1, num2){                var b = num1 + num2;                return "hello";            }*/

        /*            1、确定你的函数要不要结果。            2、return语法，return后面写什么，外面拿到的值，就是return后面的表达式。        */        /*var res = add(10, 20);        alert(res);*/        

4, arguments

            function show(){                alert(arguments.length);                alert(arguments); //输出：object Arguments            }            show(1, 2, 3);            var arr = [1, 2, 3, 4, 5];            show(arr);

5, Exercise 1, have a small to large sequence of arrays. Now enter a number that requires it to be inserted into the array as it was originally. ([2,3,4,56,67,98]//632, write function map (arr) increases each digit in the array by 30% 3, writes the function has (arr, 60) to determine if there is a 60 element in the array, returns the Boolean type

        /*var arr = [2,3,4,56,67,98];        var num = 63;        for(var i = 0; i < arr.length; i++){            if(arr[i] > num){                arr.splice(i, 0, num);                break;            }        }*/        // alert(arr);        /*            关键：找出第一个第一个比该数大的数        */        var arr = [10, 20, 30, 40, 60];        function map(arr){            for(var i = 0; i < arr.length; i++){                arr[i] = arr[i] * 1.3;            }        }        /*map(arr);        alert(arr);*/        function has(arr, num){            var isHas = false; //假设没有            for(var i = 0; i < arr.length; i++){                if(arr[i] == num){                    isHas = true;                    break;                }            }            return isHas;        }        var res = has(arr, 60);        alert(res);

4. Generate 13-bit barcode (prior knowledge synthesis exercise)

EAN-13 Code rule: The 13th digit is the first 12 digits of the computed check code.                    For example: 690123456789? Third, the process of calculating its checksum code is:?                    1, the first 12 bits of odd digits and 6+0+2+4+6+8=26?                    2, the first 12 bits and 9+1+3+5+7+9=34?                    3, add odd and three times times with even and the 26+34*3=128?                    4, the result of the single digit: 128 single digit is 8?    5, use 10 minus this single digit 10-8=2?    So the check code is 2 (note: If the result of single digit is 0, then the check code is not (10-0=10), but 0) implementation Method Ean13 () Calculation Verification code, input 12-bit barcode, return the barcode with the verification code.                 For example: input: 692223361219 output: 6922233612192//Find a way to split this 12-digit number into each//69012345678 function BarCode (num) { 1. Take out each digit var Numarr = [] respectively;                    The store takes down each digit while (1) {if (num = = 0) {break;                    } numarr.push (num% 10);                num = parseint (NUM/10);                } numarr.reverse ();                2. Find odd and even and var odd = 0;                var even = 0;  for (var i = 0; i < numarr.length; i++) {if (i% 2 = = 0) {                      Odd digit odd + = Numarr[i];                    }else{//even digit even + = Numarr[i];                }}//3, var tmp = (odd + even * 3)% 10;                if (tmp! = 0) {tmp = 10-TMP;                } numarr.push (TMP);            Return number (Numarr.join (""));            } var res = BarCode (690123456789?); Alert (res);

5. Write the function norepeat (arr) to remove the repeating elements of the array and return the new array

/*
Reverse the Delete
"Note" All traverse the data to go heavy, all backwards deletes.
*/

                function noRepeat(arr){                //去重                //选择arr.length - 1个数 和后面进行比较                //i选出的数                /*for(var i = 0; i < arr.length - 1; i++){                    //j被比的数                    for(var j = i + 1; j < arr.length; j++){                        if(arr[i] == arr[j]){                            arr.splice(j, 1);                        }                    }                }*/                for(var i = arr.length - 1; i > 0; i--){                    for(var j = i - 1; j >= 0; j--){                        if(arr[i] == arr[j]){                            arr.splice(j, 1);                        }                    }                }            }            var arr = [10, 20, 20, 20, 30, 20, 40, 50];            noRepeat(arr);            alert(arr);

6. Monkeys Eat Peach

The strongest rule of kings:
1, find the critical value, the critical value is, do not calculate, direct mental arithmetic to derive the value.
2. Find out the relationship between Nth and n-1 times
3, assuming that the function can already be used, write the formula between N and N-1.

        有一堆桃子不知数目，猴子第一天吃掉一半，觉得不过瘾，        又多吃了一只，第二天照此办法，吃掉剩下桃子的一半另加一只，        天天如此，到第num(num <= 10)天早上，猴子发现只剩一只桃子了，        问这堆桃子原来有多少只？            n为还剩n天吃完的桃子数    分析：                peach(10) / 2 - 1 = peach(9);                peach(10) = (peach(9) + 1) * 2;                peach(n) = (peach(n - 1) + 1) * 2;                    function peach(n){                if(n == 1){                    return 1;                }                return (peach(n - 1) + 1) * 2;            }            //46            var res = peach(5);            alert(res);

7. Ciphertext

/*                某个公司采用公用电话传递数据，数据是四位的整数，                在传递过程中是加密的，加密规则如下：                    1、每位数字都加上5,                    2、然后用除以10的余数代替该数字，                    3、再将第一位和第四位交换，                    4、第二位和第三位交换，请编写一个函数，传入原文，输出密文            */            //4 3 2 1            function ciphertext(num){                //1、拆成数组                var numArr = [];                while(1){                    if(num == 0){                        break;                    }                    numArr.push(num % 10);                    num = parseInt(num / 10);                }                for(var i = 0; i < numArr.length; i++){                    numArr[i] += 5;                    numArr[i] = numArr[i] % 10;                }                                return Number(numArr.join(""));            }            var res = ciphertext(1234);            alert(res);

8. Calculator

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6-1 Array function exercises