Phase 4 - Randomly Insert Single Bit Error

What to do

Fulfill the requirement "randomly insert a single bit error into the frame checksum field before a frame is sent"

How to flip a random bit of a 32-bit checksum. (Need help? Please check bitTwiddle.pdf )

• Convert the CRC into a 4-byte character array 
• Randomly choose a byte of that character array and then choose a bit of that byte 
• Generate the mask for that byte
• Xor the chosen byte with the mask

Useful Resources
Bitwise operators in C, a tutorial.
http://www.cprogramming.com/tutorial/bitwise_operators.html
Generate an random integer within range in C.
http://stackoverflow.com/questions/822323/how-to-generate-a-random-number-in-c

code snippet

#include 
#include 

srand(time(NULL)); //only need to be called once for each thread
int r = rand()%range; //returns a integer between 0 and range-1, inclusive

The most efficient way to implement an integer based power function pow(int, int) (Proved correct)
http://stackoverflow.com/questions/101439/the-most-efficient-way-to-implement-an-integer-based-power-function-powint-int !!!

Convert a 4-byte char array into a 32-bit int !!!
code snippet

unsigned int CharArrToUnsignedInt(char * charArr)
{
    unsigned int i = *(int *)charArr;
}