Question

java 中怎样用mid函数依次取字符串中字符？

package 统计字符串中不同字符个数;

import java.util.Scanner;

public class abc11 {

public static void main(String args[]){
Scanner sc=new Scanner(System.in);
System.out.print("请输入一行字符串：");
String s=sc.nextLine();
int num=1;
int i = 0;
int j;
int m=i-1;
int f=1;

for(i=1;i<=s.length();i++){
String s1=mid(s,i-1,1);
back:for(j=0;j<i;j++){
String s2=mid(s,j-1,1);
if(s1==s2){
break back;
}
else{
if(j==i-1){
num++;
}
}

}

}
System.out.println(num);
}

private static String mid(String s, int m, int f) {
// TODO Auto-generated method stub

return null;
}

}

Answer 1

private static String mid(String s, int m, int f) {
return s.substring(m,f);
}