java - Java 中的二进制到二进制转换器

Question

试图在 Java 中将二进制转换为 denary，但我不确定出了什么问题，我感觉它在我的循环中，任何帮助将不胜感激!如果你想看的话，我正在关注伪代码!

System.out.println("Enter a binary number");

Scanner sc = new Scanner(System.in);
String binaryString = sc.next();

int binaryLength = binaryString.length();

int multiplier = 1;
int denaryValue = 0; 

for(int n = binaryLength; n >= 1; n--){
    int digit = n;
    denaryValue = denaryValue + digit * multiplier;
    multiplier = multiplier * 2;
}
System.out.println("The denary equivalent is " + denaryValue);

Answer 1

绝对最简单的方法是使用 Integer.parseInt(String, 2); (在您的情况下:Integer.parseInt(binaryString, 2);)。

但是，如果你真的想运行循环:

for(int n = binaryLength; n >= 1; n--){
    int digit = binaryString.charAt(n - 1) - '0';
    denaryValue = denaryValue + digit * multiplier;
    multiplier = multiplier * 2;
}

就个人而言，如果我真的想重新发明轮子，我会这样做:

if (!binaryString.matches("[01]+")) {
    //here we know that there is a character that is not a 0 or a 1
    //or that the string is empty
}
for(char c : binaryString.toCharArray()) {
    denaryValue += c - '0';
    denaryValue <<= 1; //binary left shift; multiply by 2
}
denaryValue >>= 1; //binary right shift; divide by 2