// pruneTree.c: input and print a BST, then prune its leaves
#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
typedef struct node {
int value;
struct node *left;
struct node *right;
} Node;
typedef Node *Tree;
Node *newNode(int v); // make a new node, from lecture
Tree insert(Tree t, int v); // insert a node 'v' into a BST, from lecture
void printTree(Tree t, int level); // pretty-print a BST, from Week 10 Lab
void freeTree(Tree t); // free the tree, from Week 10 Lab
Tree pruneLeaves(Tree t); // prune the leaves on a tree
int main(int argc, char **argv) {
Tree t = NULL;
int i;
int retval = EXIT_SUCCESS;
if (argc == 1) {
fprintf(stderr, "Usage: %s integers ...\n", argv[0]);
retval = EXIT_FAILURE;
} else {
int dataGood = 1;
for (i=1; i<argc && dataGood; i++) {
int num;
if (sscanf(argv[i], "%d", &num) != 1) {
fprintf(stderr, "Usage: %s integers ...\n", argv[0]);
freeTree(t);
dataGood = 0;
retval = EXIT_FAILURE;
} else {
t = insertTree (t, num);
}
}
if (dataGood) {
printTree(t, 0);
printf("Pruned tree:\n");
t = pruneLeaves(t);
printTree(t, 0);
freeTree(t);
}
}
return retval;
}
Tree pruneLeaves(Tree t){ // delete leaf nodes
if (t != NULL) {
if (t->left==NULL && t->right==NULL) {
free(t);
t = NULL;
} else {
t->left = pruneLeaves(t->left);
t->right = pruneLeaves(t->right);
}
}
return t;
}
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// merge3.c: merge the lines in 3 files, line by line
#include <stdio.h>
#include <stdlib.h>
int main (int argc, char *argv[]) {
int retval = EXIT_SUCCESS;
FILE *fp1, *fp2, *fp3;
char line[BUFSIZ];
if (argc == 4) {
int fin1, fin2, fin3;
if ((fp1 = fopen(argv[1], "r")) != NULL &&
(fp2 = fopen(argv[2], "r")) != NULL &&
(fp3 = fopen(argv[3], "r")) != NULL) {
fin1 = 0; // assume no file is at end
fin2 = 0;
fin3 = 0;
while (!fin1 || !fin2 || !fin3) { // check whether any still going
if (fgets(line, BUFSIZ, fp1) == NULL) {
fin1 = 1; // file 1 is at end
} else {
fputs(line, stdout);
}
if (fgets(line, BUFSIZ, fp2) == NULL) {
fin2 = 1; // file 2 is at end
} else {
fputs(line, stdout);
}
if (fgets(line, BUFSIZ, fp3) == NULL) {
fin3 = 1; // file 3 is at end
} else {
fputs(line, stdout);
}
}
fclose(fp1);
fclose(fp2);
fclose(fp3);
} else {
fprintf(stderr, "Error in opening file\n");
retval = EXIT_FAILURE;
}
} else {
fprintf(stderr, "Usage: %s <fname1> <fname2> <fname3>\n", argv[0]);
retval = EXIT_FAILURE;
}
return retval;
}
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// randword.c: generate a random word. The size of the
// word and the seed of the random number generator used to
// generate the word are specified on the command line.
#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include <string.h>
int main(int argc, char *argv[]) {
int retval = EXIT_SUCCESS;
char *alphabet = "abcdefghijklmnopqrstuvwxyz";
int size = strlen(alphabet); // compute the size of the alphabet
int length;
int seed;
if (argc == 3 &&
sscanf(argv[1], "%d", &length) &&
sscanf(argv[2], "%d", &seed)) {
srandom(seed); // seed comes from the command line
char *string;
string = (char *)malloc((length+1) * sizeof(char)); // +1 for the \0
assert(string != NULL);
int i;
for (i=0; i<length; i++) {
int ran = random()%size; // size=26, so 0<=rn<=25
string[i] = alphabet[ran];
}
string[length] = '\0';
printf("%s\n", string);
free(string);
} else {
fprintf(stderr, "Usage: %s wordlength randomseed\n", argv[0]);
retval = EXIT_FAILURE;
}
return retval;
}
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// llrandword.c: generate a linked list from random word, then reverse the list.
#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include <string.h>
typedef struct _node {
char data;
struct _node *next;
} NodeT;
typedef NodeT *List;
List reverseList(List);
List buildList(char *);
void printList(List);
void freeList(List);
int main(int argc, char *argv[]) {
int retval = EXIT_SUCCESS;
List head;
char *alphabet = "abcdefghijklmnopqrstuvwxyz";
int size = strlen(alphabet); // compute the size of the alphabet
int length;
int seed;
if (argc == 3 &&
sscanf(argv[1], "%d", &length) &&
sscanf(argv[2], "%d", &seed)) {
srandom(seed); // start with this seed
char *string;
string = (char *)malloc((length+1) * sizeof(char)); // +1 for the \0
assert(string != NULL);
int i;
for (i=0; i<length; i++) {
int ran = random()%size;
string[i] = alphabet[ran];
}
string[length] = '\0';
head = buildList(string);
free(string);
printList(head);
head = reverseList(head);
printList(head);
freeList(head);
} else {
fprintf(stderr, "Usage: %s length seed\n", argv[0]);
retval = EXIT_FAILURE;
}
return retval;
}
List reverseList(List head) {
NodeT *prev = NULL;
NodeT *cur = head;
NodeT *temp;
while (cur != NULL) {
temp = cur->next;
cur->next = prev; // reverse current pointer
prev = cur; // move to ...
cur = temp; // ... next element
}
return prev;
}
List buildList(char *string) { // string had better be null terminated
NodeT *head = NULL;
NodeT *prev = NULL;
char *p;
for (p = string; *p != '\0'; p++) {
NodeT *n = (NodeT *)malloc(sizeof(NodeT));
assert(n != NULL);
n->data = *p;
n->next = NULL;
if (p == string) { // if first iteration ...
head = n; // ... it is the head
} else {
prev->next = n; // back-patch the prev node
}
prev = n; // this node becomes prev
}
return head;
}
void printList(List head) {
NodeT *n;
for (n = head; n != NULL; n = n->next) {
if (n != head) {
printf("->");
}
printf("%c", n->data);
}
putchar('\n');
}
void freeList(List head) {
NodeT *n = head;
while (n != NULL) {
NodeT *m = n->next; // remember next node before freeing this node
free(n);
n = m;
}
}
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