Name this program one. c - Complete the program shown below. #include #include typedef struct letter {char ch; struct letter *next;} Letter; int main (void) {Letter a, b, c, d, e, f, g, h, i; ch = 'D'; next = &b; ch = 'O'; next = &c; ch = 'R'; next = &d; ch = 'M'; next = &e; ch = 'I'; next = &f; ch = 'T'; next = &g; ch = 'O'; next = &h; ch = 'R'; next = &i; ch = 'Y'; next = NOLL; Letter *ptr = &a; while (ptr != NULL) {printf("%c ", ptr rightarrow ch); ptr = ptr rightarrow next;} printf (" ");//rearrange pointers so that it spells "DIRTYROOM" ptr - sa; while (ptr != NULL) {printf("%c ", ptr rightarrow ch); ptr = ptr rightarrow next;} printf (" "); return 0;} Name this program two. c - In your one. c program, replace the line shown in blue below with the line shown in red. Modify the rest of your program (including insertion of the necessary malloc statements) so that your program runs the same as your one. c program runs. Letter a, b, c, d, e, f, g, h, i; Letter *a, *b, *c, *d, *e, *f, *g, *h, *i; Name this program three. c - Repeat program two. c using an array of thirteen "Letters" that initially contains the phrase ELEVENPLUSTWO (allocate space, assign values, print the list). Then modify pointers in the data array so that it says TWELVEPLUSONE. Print this revised list. Your second print loop would start at data[10] if you encoded the original message in location 0..12 of the data array. Letter *data[13]; For all problems, modify pointers to transform the word. Modifying character values is unacceptable. Name this program three. c - Repeat program two. c using an array of thirteen "Letters" that initially contains the phrase ELEVENPLUSTWO (allocate space, assign values, print the list). Then modify pointers in the data array so that it says TWELVEPLUSONE. Print this revised list. Letter *data[13]