C :

#include<stdio.h>  
int main()  
{  
    int a,b,i,d,c,j;  
    scanf("%d%d",&a,&b);  
    if(a<=b&&a>=2&&a<=10000&&b<=10000)  
    {  
        for(i=a;i<=b;i++)  
        {  
            d=1;  
            for(j=2;j<i;j++)  
            if(i%j==0)  
            {   
                d=0;  
                break;  
            }  
            if(d==1)  
            printf("%d=%d\n",i,i);  
            else if(d==0)  
            {  
                printf("%d=",i);  
                j=2;  
                c=i;  
                while(1)  
                {  
                    while(c%j==0)  
                    {  
                        printf("%d",j);  
                        c=c/j;  
                        if(c!=1)  
                        printf("*");  
                    }  
                    if(c==1)  
                    {  
                        printf("\n");  
                        break;  
                    }  
                    j++;  
                }  
            }  
        }  
    }  
    return 0;  
}  

Java :

import java.util.*;
public class Main {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Scanner sc = new Scanner(System.in);
        int a = sc.nextInt();
        int b = sc.nextInt();
        for(int i=a; i<=b; i++)
        {
            if (i >= 3)
            {
                String m = "";
                int k = 2;
                int j = i;
                while (j != k) 
                {
                    if (j % k == 0) 
                    {
                        m = m + k + "*";
                        j = j / k;
                    }
                    else if (j % k != 0) 
                    {
                        k++;
                    }
                }
                m = m + k;
                System.out.println(i + "=" + m);
            }
            else 
            {
                System.out.println(i + "=" + i);
            }
        }
    }
}