This exercise is from Ch12, Programming Project 2b, p275/276.

Write a program called palindrome.c which has a function check_palindrome() . Your main() function must read an input string from the user, then make a call to check_palindrome() to confirm whether it's a palindrome (the letters in the message are the same from left to right as from right to left).

If it is a palindrome, the function should return 1 ; if it is not a palindrome, it should return 0 . Based on the return value of check_palindrome() , your main() function must print an appropriate output message.

A user input string will have at most 100 characters.

Your check_palindrome() function must be case-insensitive (i.e., "A" should be treated as equal to "a") and ignore all characters that are not letters.

Your program MUST use pointers and NOT integer array indices (i.e., a[1], a[5] etc.) to process the character array. You will get a 0 on this part if your program uses integer array indices instead of pointers.

Examples:

Enter a message: He lived as a devil, eh?

Palindrome

Enter a message: Madam, I am Adam.

Not a palindrome

This exercise is based on a combination of Exercise 12 from Ch12 and Programming Project 18 from Ch13.

You are provided a file called get_extension.c that has the following function prototype:

int get_extension(const char *file_name);

where file_name is a string containing a file name. Your task is to implement this function as follows: The function processes the passed file name to find the file extension and returns the index of this file extension from a lookup array called extensions . The function must declare extensions as a static array of pointers to strings that stores the following file extensions in this exact order:

.txt .out .bkp .dot .tx

For example, if the input file name is memo.txt , the function will return 0. If the file name is memo.tx.dot , the function will return 3. If the file name doesn't have an extension (or the extension is not in the array), the function will return -1. Keep the function as simple as possible by having it use functions from the string library such as strlen , strncpy , strcmp , etc

To test your get_extension() function, the provided program's main() function takes the file name as a program argument and passes it to get_extension() . The main() function then prints the value returned by get_extension() to stdout .

You can safely assume that the program will always be provided with an argument. You do not need to do any argument validation for this exercise. You can assume that the file name will have at most 20 characters, including the extension

This is based on Ch12, exercise 17. Recall how 2D arrays are represented in memory.

You are provided a C file called sum-2d-array.c that contains the function sum_two_dimensional_array shown below. You are also provided a Makefile that compiles the program. Rewrite the given function to use pointer arithmetic instead of array subscripting. In other words, eliminate the variables i and j and all uses of the [] operator.

Use a single loop instead of nested loops and do not change the function signature. You will get a 0 on this part if your program uses integer array indices instead of pointers, or if it uses a nested loop.

int sum_two_dimensional_array(int a[][LEN], int n){

int i, j, sum = 0;

for (i = 0; i < n; i++)

for (j = 0; j < LEN; j++)

sum += a[i][j];

return sum;

}

The following is the expected output of the program. This output should remain the same after you re-write the sum_two_dimensional_array function.

The sum of all elements of the array is: 120