Question

C programming. please include comments

In this lab, you will learn to read data from and write data to a file - another use for pointers. SAMPLE PROGRAM There are two sample programs this week - WriteFile.c and ReadFile.c. The first, WriteFile.c, allows the user to enter customer names (first, middle, and last), and writes each name to an output text file, customerNames.txt. formatted as: firstName middlelnitial lastName" After you've run it once, what happens to the names you added the first time if you run the program a second time and add new names? What happens if you change the access mode from 'w' to 'a'? The second file, ReadFile.c, simply opens the previously created customerNames.txt file and displays the contents of the file in the console YOUR PROGRAM For your program, you will be working with the provided text file, "inputData Names.txt You will need to create two file pointers. Use one to open "inputData Names.txt" for reading, and the other to open a file called "formattedData-Names.txt" for writing. Note: In order to open your text file, you will either need to provide the full path to the file in the fopen() call, or, more simply, put the text file in the project folder where your.c file is created. Once your files are open, read through the inputData file one line at a time. For each line, read the entire ine into a character array. Pass the array into a function using a constant pointer to non-constant data. You will need to use pointer arithmetic to navigate through the array, since you cannot change the pointer itself

Answer 1

1. #include <stdio.h>

2. int main ()

3. {

4. int c = 0;

5. char ch, s[1000];

6. printf("Input a string\n");

7. gets(s);

8. while (s[c] != '\0') {

9. ch = s[c];

10.   if (ch >= 'A' && ch <= 'Z')

11. s[c] = s[c] + 32;

12.   else if (ch >= 'a' && ch <= 'z')

13. s[c] = s[c] - 32;  

14. c++;  

15. }

16. printf("%s\n", s);

17. return 0;

18. }