JavaScript第四天练习

1.数组去重

<script>
    var arr = [10,0,20,95,30,0,50,60,70,80,0,90];
    var newArr = [];
    for(var i = 0; i < arr.length; i++) {
        if(arr[i] != 0) {
            newArr[newArr.length] = arr[i];
        }
    }
    console.log(newArr);
</script>

2.数组首尾调换

<script>
    var arr = [20, 50, 60, 80, 90];
    for(var i = 0; i < arr.length / 2; i++) {
        var temp = arr[i];
        arr[i] = arr[arr.length - 1 - i];
        arr[arr.length - 1 - i] = temp;
    }
    console.log(arr);
</script>

3.数组排序

<script>
    var arr = [120, 520, 60, 80, 90];
    for(var i = 0; i < arr.length - 1; i++) {
        for(var j = 0; j < arr.length - 1 - i; j++) {
            if(arr[j] > arr[j + 1]) {
                var temp = arr[j];
                arr[j] = arr[j + 1];
                arr[j + 1] = temp;
            }
        }
    }
    console.log(arr);
</script>

4.函数练习

<script>
    function nova() {
        var sum = 0;
        for(var i = 0; i <= 100; i++) {
            sum += i;
        }
        console.log("1到100的和：" + sum);
    }
    nova();
</script>

<script>
    function nova(x, y) {
        var sum = x + y;
        console.log(sum);
    }
    nova(10, 20);
</script>

5.函数练习

<script>
    function nova(x, y) {
        var sum = x + y;
        alert("总和是：" + sum);
    }
    var num1 = parseInt(prompt("请输入第一个数字"));
    var num2 = parseInt(prompt("请输入第二个数字"));
    nova(num1, num2);
</script>

<script>
    function getSum(x, y) {
        var sum = x + y;
        return sum;
    }
    var result = getSum(10, 20);
    console.log(result + 50);
</script>

6.函数练习

<script>
    function getSum(x, y) {
        return x + y;
    }
    var result = getSum(10, 20);
    console.log(result + 50);
</script>

<script>
    function getSum(n, y) {
        var sum1 = 0;
        for(var i = n; i <= y; i++) {
            sum1 += i;
        } 
        return sum1;
    }
    var result = getSum(2, 200);
    console.log(result);
</script>

<script>
    function jieCheng(num) {
        var sum = 1;
        for(var i = 1; i <= num; i++) {
            sum *= i;
        }
        return num + "的阶乘是：" + sum;
    }
    var result = jieCheng(6);
    console.log(result);
</script>

7.函数数组首尾调换

<script>
    function reverseArray(arr) {
        for(var i = 0; i < arr.length / 2; i++) {
            var temp = arr[i];
            arr[i] = arr[arr.length - 1 - i];
            arr[arr.length - 1 - i] = temp;
        }
        return arr;
    }
    var result = reverseArray([2, 65, 52, 84, 99]);
    console.log(result);
</script>

8.函数数组排序

<script>
    function sortArray(arr) {
        for(var i = 0; i < arr.length - 1; i++) {
            for(var j = 0; j < arr.length - 1 - i; j++) {
                if(arr[j] < arr[j + 1]) {
                    var temp = arr[j];
                    arr[j] = arr[j + 1];
                    arr[j + 1] = temp;
                }
            }
        }
        return arr;
    }
    var result = sortArray([20, 68, 87, 88, 660]);
    console.log(result);
</script>

9.函数斐波那契数列

<script>
    function getFib(num) {
        var num1 = 1;
        var num2 = 1;
        var sum = 0;
        for(var i = 3; i <= num; i++) {
            sum = num1 + num2;
            num1 = num2;
            num2 = sum;
        }
        return sum;
    }
    var result = getFib(12);
    console.log(result);
</script>

10.函数自调用小计算器

<script>
    (function nova(x, y, z) {
        var x = Number(prompt("请输入数字"));
        var y = Number(prompt("请输入第二个数字"));
        var z = prompt("请输入运算符");
        if(z == "+") {
            alert(x + z + y + "=" + (x + y));
        } else if(z == "-") {
            alert(x + z + y + "=" + (x - y));
        } else if(z == "*") {
            alert(x + z + y + "=" + (x * y));
        } else if(z == "/") {
            alert(x + z + y + "=" + (x / y));
        } else if(z == "%") {
            alert(x + z + y + "=" + (x % y));
        } else {
            alert("请输入正确");
        }
    })();
</script>