在for循环中，只有count变量正在更新，而其他变量则没有更新

for (let count = 0; count < 5; count++) {
    // 假设这里只有 count 变量更新
    console.log(count);
}

let value1 = 0;
let value2 = 0;

for (let count = 0; count < 5; count++) {
    value1 += 1; // 更新 value1
    value2 *= 2; // 更新 value2
    console.log(`count: ${count}, value1: ${value1}, value2: ${value2}`);
}

let count = 0;
let value1 = 10;
let value2 = 5;

for (count = 0; count < 5; count++) {
    value1 += 2; // 每次循环增加 2
    value2 -= 1; // 每次循环减少 1
    console.log(`count: ${count}, value1: ${value1}, value2: ${value2}`);
}

count: 0, value1: 12, value2: 4
count: 1, value1: 14, value2: 3
count: 2, value1: 16, value2: 2
count: 3, value1: 18, value2: 1
count: 4, value1: 20, value2: 0