Java - 将 2 个数字相加（作为字符串，不能使用 parse.int）

Question

I need to have 2 command line arguments as 2 numbers that are strings. Then using a loop, add the numbers together. For example,

Java AddStrings 123 456

The sum is: 579

It's for an assignment in class, having trouble figuring out what the loop would be. I can't just convert the strings to integers using parse.Int either. Any ideas?

Answer 1

Basically you find the length of the string. Loop over each individual character (I would start at the end of the string and work backwards). Then for each iteration of the loop you would take the char convert that to an int (through type casting) and add it to your total. Each time you step make sure to multiple your number by a power of ten. take that value then add them and then output your answer. (not gonna give you code cus its a homework assignment ;) )

Answer 2

int a = Integer.valueOf(args[0]);
int b = Integer.valueOf(args[1]);

Very simple. I found a lot just looking at Google. Or:

Integer i = new Integer(args[x]);

Answer 3

Try this one:-

First,you take the input.Let s1 and s2 be the 2 strings.The required loop is like this:-

String ar[]={s1,s2};
int n=0;
for(int i=0;i<2;i++)
n+=Integer.parseInt(ar[i]);
System.out.println("The sum is:-"+n);

Answer 4

Just use "+" to add them together. I think that you are overthinking the question.

Answer 5

  public String addStrings(String num1, String num2) {
      StringBuilder sb = new StringBuilder();
      int carry = 0;
      int i = num1.length() - 1;
      int j = num2.length() - 1;

      while (i > -1 || j > -1) {
          int sum = carry + (i < 0 ? 0 : num1.charAt(i--) - 48);
          sum += j < 0 ? 0 : num2.charAt(j--) - 48;
          sb.append(sum % 10);
          carry = sum / 10;
      }
      return sb.append(carry == 1 ? "1" : "").reverse().toString();
  }