我需要要求用户输入一个 3 位数字,然后使用 for 循环交换第一个和最后一个数字。这就是我到目前为止所拥有的,但我被困住了。使用 for 循环似乎不合逻辑,但这就是我必须做的:
num = prompt("Please input a number with 3 digits.");
let firstDigit = num[0];
let secondDigit = num[1];
let lastDigit = num[2];
for (firstDigit < 10; secondDigit < 10; lastDigit < 10); {
console.log(lastDigit + secondDigit + firstDigit);
}
请帮忙!
谢谢
对你有帮助吗?
// let num = prompt("Please input a number with 3 digits.");
// if (num.length > 3) alert("3 digits please");
// else {
// let answer = "";
// for (var i = 2; i >= 0; i--) {
// answer = answer + num[i];
// }
// console.log(answer);
//}
let num = prompt("Please input a number");
let temp = "";
let answer = "";
for(let i = 0 ; i < num.length; i++) {
if (i === 0) temp = num[i]; // save first number to temp
else if (i === num.length - 1) {
// When the last number is encountered, the last number is put at the beginning, and the first number stored in temp is put at the end.
answer = answer + temp;
answer = num[i] + answer;
}
else answer = answer + num[i];
}
console.log(answer);
那么你如何更改此代码以交换第二位数字和最后一位数字,因为我只能更改代码以交换第一位和第二位?
let num2 = "";
let Newnum = "";
for ( i = 0; i < Entnum.length; i++) {
if (i === 0) num2 = Entnum[i];
else if (i === Entnum.length - 2) {
Newnum = Newnum + num2;
Newnum = Entnum[i] + Newnum;
}
else Newnum = Newnum + Entnum[i];
}
console.log("New number:" + Newnum)