lab9网络技术

// LAB_9.js

// Task -1: Else statement
function task1() {
    let result = prompt("Enter your password:");
    if (result === "1234") {
        alert("Login completed");
    } else {
        alert("Login denied");
    }
}

// Task -2: Else if statement
function task2() {
    let result = prompt("Enter your password:");
    if (result === "1234") {
        alert("Login completed");
    } else if (result === "4321") {
        alert("Login completed with alternative password");
    } else {
        alert("Login denied");
    }
}

// Task -3: Comparison operators
function task3() {
    let x = 5;
    let y = "5";
    console.log(x === y); // false
    console.log(x == y);  // true
}

// Task -4: Logical OR
function task4() {
    let password = prompt("Enter your password:");
    if (password === "1234" || password === "4321") {
        alert("Login allowed");
    } else {
        alert("Login error:( ");
    }
}

// Task -5: Logical AND
function task5() {
    let login = prompt("Enter your login:");
    let password = prompt("Enter your password:");
    if (login === "admin" && password === "1234") {
        alert("Login allowed");
    } else {
        alert("Login error:( ");
    }
}

// Task -6: Logical NOT
function task6() {
    let password = prompt("Enter your password:");
    if (!(password === "1234")) {
        alert("Login denied");
    } else {
        alert("Login allowed");
    }
}

// Task -7: If-else example
function task7() {
    let a = 50;
    let b = 70;
    if (a > b) {
        console.log(a + b);
    } else {
        console.log(a * b); // Outputs 3500
    }
}

// Task -8: Nested conditions
function task8() {
    let a = 50;
    let b = 70;
    if (a > 10 && b > 70) {
        a = a + 10;
        b = b * 2;
        console.log(a + b);
    } else if (a > 40 && b > 40) {
        a = a + 50;
        b = a * b;
        console.log(b); // Outputs 3500
    } else {
        console.log(0);
    }
}

// Task -9: User access function
function task9(login) {
    switch (login) {
        case "admin":
            console.log("Administration, Operations, Statistics, Roles");
            break;
        case "support":
            console.log("Operations, Statistics");
            break;
        case "user":
            console.log("Statistics");
            break;
        default:
            console.log("Invalid login");
    }
}

// Task -10: Discount calculation
function task10() {
    let check = prompt("Enter the purchase amount:");
    check = parseInt(check);
    if (check >= 750) {
        check = check - (check * 5 / 100);
        check = Math.floor(check);
    }
    console.log(check);
}

// Task -11: For loop sum
function task11() {
    let n = 6;
    let s = 10;
    for (let i = 0; i < n; i++) {
        s = s + i;
    }
    console.log(s); // Outputs 25
}

// Task -12: For loop multiplication
function task12() {
    let n = 6;
    let p = 1;
    for (let i = 0; i < n; i++) {
        p = p * i;
    }
    console.log(p); // Outputs 0
}

// Task -13: Sum purchases over n visits
function task13() {
    let n = parseInt(prompt("Enter the number of visits:"));
    let total = 0;
    for (let i = 0; i < n; i++) {
        let s = parseInt(prompt("Enter purchase amount:"));
        total += s;
    }
    console.log(total);
}

// Task -14: getSum function
function getSum(a, b, c) {
    return a + b + c;
}

// Main function to execute tasks
function main() {
    console.log("Starting Task -1");
    task1();
    
    console.log("Starting Task -2");
    task2();
    
    console.log("Starting Task -3");
    task3();
    
    console.log("Starting Task -4");
    task4();
    
    console.log("Starting Task -5");
    task5();
    
    console.log("Starting Task -6");
    task6();
    
    console.log("Starting Task -7");
    task7();
    
    console.log("Starting Task -8");
    task8();
    
    console.log("Starting Task -9");
    task9("admin"); // Change parameter as needed
    
    console.log("Starting Task -10");
    task10();
    
    console.log("Starting Task -11");
    task11();
    
    console.log("Starting Task -12");
    task12();
    
    console.log("Starting Task -13");
    task13();
    
    console.log("Starting Task -14");
    console.log(getSum(1, 2, 3)); // Outputs 6
}

// Execute the main function
main();