Hi,

I have to modify the below program to use a signal handler, implementing a timer. The sleep to be replaced with sighandler, itimerval, sigaction etc...

/ Program 4: Reading values at regular time intervals // Done By Vishal Murugavel #include #include #include #include #include #include #include #include #include

// This is a structure class that is used to read data from // the file where character as letter and short integer as the the number struct pairs { char letter; short int number; };

// Function to count the number of set bits in a binary representation int count_set_bits(int num1) { int count = 0; while (num1) { count += num1 & 1; // Doing bit-wise comparision with the AND (&) Operator and the number 1 num1 >>= 1; // The binary bit shifts to the right by one digit } return count; }

// This is the main program that reads the data file int main() { char c; int num; FILE *file1; // This is where the FILE *file pointer is used to access the file struct pairs char_int; // We are declaring char_int as the structure file1 = fopen("error.dat", "rb"); // The file image.dat is being opened and assigned the // pointer to File 1

if(!file1) // This is a if-condition loop to check if error occurs while opening file { printf("File cannot be opened or found "); return 1; }

// Read a character-integer pair every second while (fread(&char_int, sizeof(struct pairs), 1, file1)) // This loop continues until the end of a file or when an error occurs // It reads all the data from the file and moves the values to the // structure char_int { // Compute the parity of the pair c = char_int.letter; num = char_int.number;

int parity = count_set_bits(c) + count_set_bits(num); // Adding counting number of bits set to 1 in both char and integer

if (parity % 2 == 0) // Checking if parity is even using % operator { // If parity is even, the data is valid

int original_num = num; //printf(" step 3 num (%d)",num); printf("(%c, %d) ",c ,original_num); // This will give the original value of the character and pr for (int i = 0; i < char_int.number; i++) // This loop is used to display the decoded form of the pairing of character and integer // by printing the character so many times until it reaches the value of the integer // It will start from 0 and continues until i is less than integer { printf("%c", char_int.letter); // This print function is used to print the character // retrieved from the file } printf(" "); // Each record is printed on a new line } else { // The parity is odd, so the data is corrupted printf("Error: Odd parity "); } sleep(1); // This uses a sleep system call for the specified number of seconds until interrupted // Reading 1 character integer pair every second here 1 corresponds to every second } fclose(file1); // Closing the file after successfully reading the data return 0;

}