一、题目描述

给定一个任意的字符串，统计并输出字符串中每个字符出现的次数和出现次数最多的字符。

二、解题思路

• 我们常用的字符的ASCII码是从32到127，所以我们创建一个长度为96的数组来保存32-127之间的每个字符所出现的次数。
• 然后将字符串转换为字符数组，通过增强for循环，将每个字符转换成对应的ASCII码并进行遍历。只要对应的ASCII码值在32-127，就让该字符所对应位置的数组上的元素加一。
• 如何输出数组每个索引上对应字符？由于数组的索引是从0开始，而我们要寻找的字符位于32-127，所以数组的索引加上32便是对应的字符ASCII码，通过类型转换便可以得到对应的字符。
• 寻找出现次数最多的字符的原理和寻找数组中的最大值的原理一样，先假设数组第一个元素最小并赋值给变量max，然后依次和数组中的下一个元素进行比较，如果小于下一个元素，则将下一个元素赋值给max，直到所有的元素都比较完毕，得到的max就是最大值。

三、代码示例

package com.easy.java;

/**
 * @ClassName Test06
 * @Description 输入一个字符串，统计每个字符出现的次数，和出现次数最多的字符。
 * @Author wk
 * @Date 2021/11/28 22:35
 * @Version 1.0
 */
public class Test06 {
    public static void main(String[] args) {
        String str = "Don't be afraid to shoot a single horse. What about being alone and brave? You can cry all the way, but you can't be angry. " +
                "You have to go through the days when nobody cares about it to welcome applause and flowers." +
                "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAABBBBBBBBBB";
        int strArr[] = new int[96];
        // 增强for循环
        for (int i : str.toCharArray()) {
            if (i >= 32 && i <= 127) {
                strArr[i - 32]++;
            }
        }
        for (int i = 0; i < strArr.length; i++) {
            if (strArr[i] != 0) {
            	// 得到数组每个索引上对应的字符
                char target = (char) (i + 32);
                // 输出每个字符出现的次数
                System.out.println(target + "  ---->  " + strArr[i]);
            }
        }
        // 统计出现次数最多的字符
        int max = strArr[0];
        int index = 0;
        for (int i = 0; i < strArr.length; i++) {
            if (max < strArr[i]) {
                max = strArr[i];
                index = i;
            }
        }
        if((index + 32) == 32){
            System.out.println("出现次数最多的字符是：" + "空格(space)" + ",出现次数为：" + max);
        }else {
            System.out.println("出现次数最多的字符是：" + (char) (index + 32) + ",出现次数为：" + max);
        }
    }
}

四、测评结果

• 实例一：

String str = "Don't be afraid to shoot a single horse. " +
                "What about being alone and brave? You can cry all the way, but you can't be angry. " +
                "You have to go through the days when nobody cares about it to welcome applause and flowers." +
                "AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAABBBBBBBBBB";

• 实例二

String str = "Don't be afraid to shoot a single horse. " +
                "What about being alone and brave? You can cry all the way, but you can't be angry. " +
                "You have to go through the days when nobody cares about it to welcome applause and flowers.";