Question

有人能告诉我我的代码有什么问题吗？回归正确的世纪。这是为了返回正确的世纪，（例如，1905年返回20，年1700返回17）。约束为1≤年≤2005。输入为正整数（年）。

    function centuryFromYear(year) {
    switch (year) {

    case ((year >= 1) && (year < 101)):
    return 1;
    break;

    case ((year > 100) && (year < 201)):
    return 2; 
    break;

    case ((year > 200) && (year < 301)):
    return 3;
    break;

    case ((year > 300) && (year < 401)):
    return 4;
    break;

    case ((year > 400) && (year < 501)):
    return 5;
    break;

    case ((year > 500) && (year < 601)):
    return 6;
    break;

    case ((year > 600) && (year < 701)):
    return 7;
    break;

    case ((year > 700) && (year < 801)):
    return 8;
    break;

    case ((year > 800) && (year < 901)):
    return 9;
    break;

    case ((year > 900) && (year < 1001)):
    return 10;
    break;

    case ((year > 1000) && (year < 1101)):
    return 11;
    break;

    case ((year > 1100) && (year < 1201)):
    return 12;
    break;

    case ((year > 1200) && (year < 1301)):
    return 13;
    break;

    case ((year > 1300) && (year < 1401)):
    return 14;
    break;

    case ((year > 1400) && (year < 1501)):
    return 15;
    break;

    case ((year > 1500) && (year < 1601)):
    return 16;
    break;

    case ((year > 1600) && (year < 1701)):
    return 17;
    break;

    case ((year > 1700) && (year < 1801)):
    return 18;
    break;

    case ((year > 1800) && (year < 1901)):
    return 19;
    break;

    case ((year > 1900) && (year < 2001)):
    return 20;
    break;

    case ((year > 2000) && (year <=2005)):
    return 21;
    break;



}

}

Answer 1

如果您想检查范围，则无法使用case，它需要准确的值。

switch (expression) {
  case value1:
    //Statements executed when the result of expression matches value1
    [break;]
  case value2:
    //Statements executed when the result of expression matches value2
    [break;]
  ...
  case valueN:
    //Statements executed when the result of expression matches valueN
    [break;]
  default:
    //Statements executed when none of the values match the value of the expression
    [break;]
}

针对您的问题的更通用的解决方案将类似于此：

function centuryFromYear(year) {
    return Math.floor((year-1)/100)+1
}

Answer 2

只需将year - 1除以100，然后像这样添加1：

function centuryFromYear(year) {
    return Math.floor((year - 1) / 100) + 1;
}


/* Example: */

var year = parseInt(prompt('Enter a year: '));

alert('The century is: ' + centuryFromYear(year));

有人能告诉我我的代码有什么问题吗？返回正确的世纪

2 个答案: