Program
import java.util.Scanner;
class Frequency
{
public static void main(String...s)
{
String str="";
int count=0,len=0,flag=0;
Scanner sc=new Scanner(System.in);
System.out.print("nEnter a string:");
str=sc.nextLine();
len=str.length();
for(int i=0;i<len;++i)
{
count=0;
for(int j=0;j<len;++j)
if(str.charAt(j)==str.charAt(i))
count++;
for(int k=0;k<i;++k)
if(str.charAt(k)==str.charAt(i))
flag=1;
if(flag!=1)
System.out.print(str.charAt(i)+":"+count+"n");
flag=0;
}
}
}
Output