Code for Bit manipulation

Cryptography/Caesarcipher.py

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+"""
+A Caesar Cipher function for both, encryption and decryption.
+After giving the string that you want, encryption will take place by shifting
+characters to the right and the decrypted string can be obtained by shifting
+the encrypted string to the left.
+The cipher is ready for Capital Letters only
+"""
+
+def encrypt(message,key):
+  ascii_vals_enc=[ord(c) for c in message] #To get a list of ASCII Values of each character in string
+  for i in range(0,len(ascii_vals_enc)):
+    if(ascii_vals_enc[i]>=65 and ascii_vals_enc[i]<=90):
+      ascii_vals_enc[i] = 65 + (ascii_vals_enc[i] + key - 91)%26  #If the values in the list are greater than 65 and 90, we get it back b/w 65 and 90
+  encrypt_string = ''.join(chr(i) for i in ascii_vals_enc) # To get the encrypted string using the list of manipulated ASCII vals
+  return encrypt_string
+
+def decrypt(message,key):
+  ascii_vals_dec=[ord(c) for c in message]
+  for i in range(0,len(ascii_vals_dec)):
+    if(ascii_vals_dec[i]>=65 and ascii_vals_dec[i]<=90):
+      ascii_vals_dec[i] = 90 - (90 - ascii_vals_dec[i] + key )%26
+  decrypt_string = ''.join(chr(i) for i in ascii_vals_dec) # To get the decrypted string using the list of manipulated ASCII vals
+  return decrypt_string
+
+def caesar_cipher():
+  message = raw_input("Enter text to be encrypted:")
+  encrypt_string = encrypt(message,key)
+  decrypt_string = decrypt(encrypt_string,key)
+  print encrypt_string
+  print decrypt_string
+
+if __name__=="__main__":
+  key = int(raw_input("By what value do you want to shift?"))
+  caesar_cipher()

bitmanip.c

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+#include<stdio.h>
+#define baseyear 2000
+
+void main()
+{
+	short int date;
+	short int temp,retrieve;
+
+
+	printf("Enter Date:\n");
+	scanf("%d",&temp);
+	date=temp;
+
+	printf("Enter Month:\n");
+	scanf("%d",&temp);
+	date=date|(temp<<5);
+
+	/*printf("%d\n",date);
+    printf("%d %d",temp,retrieve);*/
+
+	printf("Enter Year:\n");
+	scanf("%d",&temp);
+	date=date|(temp-baseyear)<<9;
+
+	printf("The total date information stored in 2 bytes has been encoded as follows: %d\n",date);
+
+
+	retrieve=(date<<11);
+	retrieve=retrieve>>11;
+	if(retrieve<0)
+    printf("The date is : %d\n",32+retrieve);
+    else
+    printf("The date is : %d\n",retrieve);
+
+
+    retrieve=date<<7;
+    retrieve=retrieve>>12;
+    if(retrieve<0)
+    printf("The month is : %d\n",16+retrieve);
+    else
+    printf("The month is : %d\n",retrieve);
+
+
+    retrieve=date>>9;
+    if(retrieve<0)
+    printf("The year is : %d\n",128+retrieve+baseyear);
+    else
+    printf("The year is : %d\n",retrieve+baseyear);
+
+}

sort/shellsort.py

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+"""
+The algorithm uses a procedure called Shell Sort
+to sort the lists. It breaks the list to smaller sublists
+and each sublist is further sorted by insertion sort.
+The sublists are made using a gap and elements at gap i
+is often selected and forms a sublist.
+"""
+
+def shellSort(test):
+    sublistcount = len(test)//2 #Finds gap to create sublists
+    while(sublistcount > 0):
+	for startposition in range(sublistcount):
+		gapInsertionSort(test,startposition,sublistcount)
+	print("After increments of size",sublistcount,"The list is",test)
+	sublistcount = sublistcount // 2
+
+def gapInsertionSort(test,start,gap):
+	for i in range(start+gap,len(test),gap):
+		currentvalue = test[i]
+		position = i
+		while(position>=gap and test[position-gap]>currentvalue):
+			test[position]=test[position-gap]
+			position = position-gap
+		test[position]=currentvalue
+
+if __name__=="__main__":
+    test = [99,109,29,89,44,98,20,55,31]
+    shellSort(test)
+    print test