java - for循环只读取最后一个值

Question

我的程序中有一个错误，使我的循环仅读取输入字符串的最后一部分。我希望程序计算字符串中每个字符的数量。我不希望答案告诉我如何更有效地存储这些值，而不需要将所有内容重复 26 次。请回答我在这里提出的问题。抱歉，如果这是重复的!我只是不知道要指定什么，因为没有明显的错误。

import java.util.Scanner;

public class stringprogram {
    public static void stringinputmethod()
    {
        Scanner scan = new Scanner(System.in);
        System.out.println("Enter a String");
        String strs = scan.nextLine();

        int numa = 0;
        int numb = 0;
        int numc = 0;
        int numd = 0;
        int nume = 0;
        int numf = 0;
        int numg = 0;
        int numh = 0;
        int numi = 0;
        int numj = 0;
        int numk = 0;
        int numl = 0;
        int numm = 0;
        int numn = 0;
        int numo = 0;
        int nump = 0;
        int numq = 0;
        int numr = 0;
        int nums = 0;
        int numt = 0;
        int numu = 0;
        int numv = 0;
        int numw = 0;
        int numx = 0;
        int numy = 0;
        int numz = 0;

        String randaf;

        for(int i=0; i<=strs.length();i++)
        {
            randaf = strs.substring(i);

            if(randaf.equals("a"))
            {
                numa = numa + 1;
            }
            else if(randaf.equals("b"))
            {
                numb = numb + 1;
            }
            else if(randaf.equals("c"))
            {
                numc = numc + 1;
            }
            else if(randaf.equals("d"))
            {
                numd = numd + 1;
            }
            else if(randaf.equals("e"))
            {
                nume = nume + 1;
            }
            else if(randaf.equals("f"))
            {
                numf = numf + 1;
            }
            else if(randaf.equals("g"))
            {
                numg = numg + 1;
            }
            else if(randaf.equals("h"))
            {
                numh = numh + 1;
            }
            else if(randaf.equals("i"))
            {
                numi = numi + 1;
            }
            else if(randaf.equals("j"))
            {
                numj = numj + 1;
            }
            else if(randaf.equals("k"))
            {
                numk = numk + 1;
            }
            else if(randaf.equals("l"))
            {
                numl = numl + 1;
            }
            else if(randaf.equals("m"))
            {
                numm = numm + 1;
            }
            else if(randaf.equals("n"))
            {
                numn = numn + 1;
            }
            else if(randaf.equals("o"))
            {
                numo = numo + 1;
            }
            else if(randaf.equals("p"))
            {
                nump = nump + 1;
            }
            else if(randaf.equals("q"))
            {
                numq = numq + 1;
            }
            else if(randaf.equals("r"))
            {
                numr = numr + 1;
            }
            else if(randaf.equals("s"))
            {
                nums = nums + 1;
            }
            else if(randaf.equals("t"))
            {
                numt = numt + 1;
            }
            else if(randaf.equals("u"))
            {
                numu = numu + 1;
            }
            else if(randaf.equals("v"))
            {
                numv = numv + 1;
            }
            else if(randaf.equals("w"))
            {
                numw = numw + 1;
            }
            else if(randaf.equals("x"))
            {
                numx = numx + 1;
            }
            else if(randaf.equals("y"))
            {
                numy = numy + 1;
            }
            else if(randaf.equals("z"))
            {
                numz = numz + 1;
            }
        }
        System.out.println("a: "+numa +"\nb: "+ numb +"\nc: "+ numc +"\nd: "+ numd +"\ne: "+ nume +"\nf: "+ numf +"\ng: "+ numg +"\nh: "+ numh +"\ni: "+ numi +"\nj: "+ numj +"\nk: "+ numk +"\nl: "+ numl +"\nm: "+ numm +"\nn: "+ numn +"\no: "+ numo +"\np: "+ nump +"\nq: "+ numq +"\nr: "+ numr +"\ns: "+ nums +"\nt: "+ numt +"\nu: "+ numu +"\nv: "+ numv +"\nw: "+ numw +"\nx: "+ numx +"\ny: "+ numy +"\nz: "+ numz);
    }

    public static void main(String[] args)
    {
        stringinputmethod();
    }
}

Answer 1

substring 方法将从指定的索引到字符串末尾返回一个新字符串。您想要的是 String.charAt(index) 它将返回指定位置的字符