diff --git a/Java/Program-12/Program-12.txt b/Java/Program-12/Program-12.java
similarity index 100%
rename from Java/Program-12/Program-12.txt
rename to Java/Program-12/Program-12.java
diff --git a/Java/Program-13/Program Number to Word.java b/Java/Program-13/Program Number to Word.java
new file mode 100644
index 00000000..2718c621
--- /dev/null
+++ b/Java/Program-13/Program Number to Word.java	
@@ -0,0 +1,120 @@
+class NumberToWordExample1   
+{  
+//user-defined static method that converts a number into words  
+static void numberToWords(char num[])  
+{  
+//determines the number of digits in the given number  
+int len = num.length;  
+//checks the given number has number or not  
+if (len == 0)   
+{  
+//if the given number is empty prints the following statement     
+System.out.println("The string is empty.");  
+return;  
+}  
+//here, we have specified the length of the number to 4  
+//it means that the number (that you want to convert) should be four or less than four digits  
+if (len > 4)   
+{  
+//if the given number is more than four-digit number, it prints the following statement    
+System.out.println("\n The given number has more than 4 digits.");  
+return;  
+}  
+//string type array for one-digit numbers    
+String[] onedigit = new String[] {"Zero", "One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine"};  
+//string type array for two digits numbers    
+//the first index is empty because it makes indexing easy   
+String[] twodigits = new String[] {"", "Ten", "Eleven", "Twelve", "Thirteen", "Fourteen", "Fifteen", "Sixteen", "Seventeen", "Eighteen", "Nineteen"};  
+//string type array of tens multiples   
+//the first two indexes are empty because it makes indexing easy   
+String[] multipleoftens = new String[] {"",  "", "Twenty", "Thirty", "Forty", "Fifty", "Sixty", "Seventy", "Eighty", "Ninety"};  
+//string type array of power of tens   
+String[] poweroftens = new String[] {"Hundred", "Thousand"};  
+//Used for debugging purpose only   
+//the valueOf() method returns the string representation of the character array argument  
+System.out.print(String.valueOf(num) + ": ");  
+//checks whether the length of the given string is one or not  
+if (len == 1)   
+{  
+//if the above condition returns true, it accesses the corresponding index and prints the value of that index  
+//[num[0]-'0']: getting the number equal the decimal value of the character (assuming the char is the digit)  
+System.out.println(onedigit[num[0]-'0']);  
+return;  
+}  
+int x = 0;  
+//executes until num does not become not '\0'  
+while (x < num.length)   
+{  
+//executes if the length of the string is greater than equal to three  
+if (len >= 3)   
+{  
+if (num[x] - '0' != 0)   
+{  
+System.out.print(onedigit[num[x] - '0'] + " ");  
+//here length can be 3 or 4  
+System.out.print(poweroftens[len - 3]+ " ");  
+}  
+//decrements the length of the string by 1  
+--len;  
+}  
+//executes if the given number has two digits  
+else   
+{  
+//the if-statement handles the numbers from 10 to 19 only     
+if (num[x] - '0' == 1)   
+{  
+//adding the digits of the given number   
+//the logic behind sum up the digits is that we will use the sum for accessing the index of the array   
+//for example: 17, sum of digits = 8  
+//we will access the 8th index in twodigits[] array i.e. Seventeen  
+int sum = num[x] - '0' + num[x + 1] - '0';  
+System.out.println(twodigits[sum]);  
+return;  
+}  
+//the else-if statement handles the number 20 only  
+//compares the tens and unit place with 2 and 0 respectively  
+else if (num[x] - '0' == 2 && num[x + 1] - '0' == 0)   
+{  
+//executes if the above else-if condition returns true    
+System.out.println("Twenty");  
+return;  
+}  
+//the else block handles the numbers from 21 to 100  
+else   
+{  
+int i = (num[x] - '0');  
+if (i > 0)  
+//prints the ith index element of the array multipleoftens[]  
+System.out.print(multipleoftens[i]+ " ");  
+else  
+//prints space  
+System.out.print("");  
+//increments the variable i by 1  
+++x;  
+//checks whether the number is not equal to zero, it means the number has only a digit  
+if (num[x] - '0' != 0)  
+//prints the ith index element of the array onedigit[]  
+System.out.println(onedigit[num[x] - '0']);  
+}  
+}  
+//increments the variable i by 1  
+++x;  
+}  
+}  
+//main() method  
+public static void main(String args[])  
+{  
+//calling the user-defined method and that invokes another predefined method toCharArray()  
+//the method toCharArray() converts the given number into character array  
+numberToWords("1111".toCharArray());  
+numberToWords("673".toCharArray());  
+numberToWords("85".toCharArray());  
+numberToWords("5".toCharArray());  
+numberToWords("0".toCharArray());  
+numberToWords("20".toCharArray());  
+numberToWords("1000".toCharArray());  
+numberToWords("12345".toCharArray());  
+//passing empty string   
+numberToWords("".toCharArray());  
+}  
+}  
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