char alphabet;
//要截取的n
int n=5;
/稿禅镇/字符袭隐串
String word=“键粗abadfafadfada”;
alphabet=word.charAt(n);
System.out.println(alphabet);
26个变量存储字符出现频率 每次都做判断
或着动态生成变量存储频率
字符串.charAt(int n)
char c = 'a';
int N = 10;
String s = xxx;
int n = 0;
for(int i = 1;i < s.length; i++) {
if(s.charAt(i) == c) {
n++;
}
if(n == N)
return i;
}