10进制与其他进制的互相转换

const CHAR_TABLE = '0123456789ABCDEF'
// 将n进制转换为10禁止
function myParseInt(s, n = 10) {
    let result = 0
    for (let c of s) {
        let value = CHAR_TABLE.indexOf(c)
        // 非法范围，直接结束
        if (value >= n || value < 0) break
        result = result * n + value
    }
    return result
}

function decimalToNBase(value, n = 2) {
    if (typeof value !== 'number') {
        try {
            value = parseInt(value)
        } catch (err) {
            throw new Error(`unable to parse ${value} as a Integer.`)
        }
    }
// 用递归栈特性，出栈顺序正好将结果倒置
    if (value > 0) {
        let remain = value % n
        let divide = Math.floor(value / n)
        return decimalToN(divide, n) + CHAR_TABLE[remain]
    }
    return '0'
}
console.log(myParseInt("011x", 8)) // 9

console.log(myParseInt("512", 16)) // 1298
console.log(myParseInt("EFF", 16)) // 3839

console.log(decimalToNBase(252, 2)) // 011111100

console.log(decimalToNBase(65321, 16)) // 0FF29

// 转换完成，又转换回来
console.log(myParseInt(decimalToNBase(65321, 16), 16)) // 65321
console.log(decimalToNBase(myParseInt('0FEA1', 16), 16)) // 0FEA1
vaakian / vaakian.github.io

10进制与其他进制的互相转换 #18
