From f7e566e033b7053f4fd67d397bd87893a585102d Mon Sep 17 00:00:00 2001
From: vyvyvyThao <wn73@drexel.edu>
Date: Sun, 19 Jan 2025 19:35:45 -0500
Subject: [PATCH] assignment 1
---
1-C/stringfun.c | 354 ++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 354 insertions(+)
create mode 100644 1-C/stringfun.c
diff --git a/1-C/stringfun.c b/1-C/stringfun.c
new file mode 100644
index 0000000..66671d7
--- /dev/null
+++ b/1-C/stringfun.c
@@ -0,0 +1,354 @@
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+
+
+#define BUFFER_SZ 50
+
+//prototypes
+void usage(char *);
+void print_buff(char *, int);
+int setup_buff(char *, char *, int);
+
+//prototypes for functions to handle required functionality
+int count_words(char *, int, int);
+//add additional prototypes here
+int wordPrint(char *buff, char user_str_len);
+void reverse(char *buff, int user_str_len);
+int wordFound(char *str, char *word);
+int replace(char *src, char *word, char *replacement, char *dest, int buff_len);
+
+
+int setup_buff(char *buff, char *user_str, int len){
+ //TODO: #4: Implement the setup buff as per the directions
+ /*
+ - Make all white spaces single space
+ - Count the length
+ - Return -1 if length > BUFFER_SZ
+ - Else: fill dots in and return length
+ */
+ int space = 0;
+ int user_str_len = 0;
+
+ while (*user_str != '\0' && user_str_len <= len) {
+ if (*user_str != ' ') {
+ *buff = *user_str;
+ buff++;
+ space = 0;
+ user_str_len++;
+
+ } else {
+ if (space == 0) {
+ *buff = *user_str;
+ buff++;
+ user_str_len++;
+ space += 1;
+ }
+ }
+ user_str++;
+ }
+
+ if (*user_str != '\0' && user_str_len > len) {
+ return -1;
+ }
+
+ int buff_curr_len = user_str_len;
+
+ while (buff_curr_len < len) {
+ *buff = '.';
+ buff++;
+ buff_curr_len++;
+ }
+
+ buff = buff - buff_curr_len;
+
+ return user_str_len;
+}
+
+void print_buff(char *buff, int len){
+ printf("Buffer: ");
+ for (int i=0; i<len; i++){
+ putchar(*(buff+i));
+ }
+ putchar('\n');
+}
+
+void usage(char *exename){
+ printf("usage: %s [-h|c|r|w|x] \"string\" [other args]\n", exename);
+
+}
+
+int count_words(char *buff, int len, int str_len){
+ if (str_len == 0) {
+ return 0;
+ }
+
+ int wc = 0;
+ for (int i = 0; i < str_len; i++) {
+ if (*buff == ' ') {
+ wc += 1;
+ }
+ buff++;
+ }
+ wc += 1;
+
+ return wc;
+}
+
+//ADD OTHER HELPER FUNCTIONS HERE FOR OTHER REQUIRED PROGRAM OPTIONS
+
+int wordPrint(char *buff, char user_str_len) {
+ int charCount = 0;
+ int wordCount = 1;
+ printf("Word Print \n----------\n");
+ printf("%d. ", wordCount);
+
+ while (*buff != '.') {
+ if (*buff != ' ') {
+ printf("%c", *buff);
+ charCount++;
+ } else {
+ printf(" (%d)\n", charCount);
+ charCount = 0;
+ wordCount++;
+ printf("%d. ", wordCount);
+ }
+
+ buff++;
+ }
+
+ printf(" (%d)\n", charCount);
+ printf("Number of words returned: %d\n", wordCount);
+
+ buff = buff - user_str_len;
+}
+
+void reverse(char *buff, int user_str_len) {
+ char temp;
+ char *end = buff + user_str_len - 1;
+
+ while (end > buff) {
+ temp = *buff;
+ *buff = *end;
+ *end = temp;
+ end--;
+ buff++;
+ }
+}
+
+int wordFound(char *str, char *word) {
+ int wordLength = 0;
+
+ while (*word != '\0') {
+ if (*str != *word) {
+ return 0; // first word in string is not the wanted word
+ }
+ wordLength++;
+ str++;
+ word++;
+ }
+
+ word = word - wordLength;
+ if (*str != ' ' && *str != '\0' && *str != '.') {
+ return 0;
+ }
+ str = str - wordLength;
+ return wordLength;
+}
+
+int replace(char *src, char *word, char *replacement, char *dest, int buff_len) {
+ int match;
+ int newWord = 1;
+ char * original_dst = dest;
+ int destLength = 0;
+ int replmLength = 0;
+
+ int wordNotFound = 1;
+
+ while (*replacement != '\0') {
+ replmLength++;
+ replacement++;
+ }
+
+ replacement = replacement - replmLength;
+
+ while (*src != '.') {
+ if (newWord) {
+ match = wordFound(src, word);
+
+ // if word to replace is found, copy replacement to dest instead
+ if (match > 0) {
+ wordNotFound = 0;
+ while (*replacement != '\0') {
+ destLength++;
+ if (destLength > buff_len) {
+ return -1;
+ }
+
+ *dest = *replacement;
+ dest++;
+ replacement++;
+ }
+ src = src + match;
+ replacement = replacement - replmLength;
+ }
+ }
+
+ if (*src == '.') {
+ break;
+ }
+
+ destLength++;
+ if (destLength > buff_len) {
+ return -1;
+ }
+ *dest = *src;
+
+ if (*src == ' ') {
+ newWord = 1;
+ } else {
+ newWord = 0;
+ }
+ dest++;
+ src++;
+ }
+
+ if (wordNotFound) {
+ return 1;
+ }
+
+ dest = dest - destLength;
+ // printf("Replaced string: %s\n", dest);
+
+
+ return destLength;
+}
+
+int main(int argc, char *argv[]){
+
+ char *buff; //placehoder for the internal buffer
+ char *input_string; //holds the string provided by the user on cmd line
+ char opt; //used to capture user option from cmd line
+ int rc; //used for return codes
+ int user_str_len; //length of user supplied string
+
+ //TODO: #1. WHY IS THIS SAFE, aka what if arv[1] does not exist?
+ // This is to validate if the command has a correct syntax and all minimum required arguments
+ // so that the following operations can run with valid inputs or the type of error can be
+ // specified to help the user fix it and find the correct command that is going to work
+ if ((argc < 2) || (*argv[1] != '-')){
+ usage(argv[0]);
+ exit(1);
+ }
+
+ opt = (char)*(argv[1]+1); //get the option flag
+
+ //handle the help flag and then exit normally
+ if (opt == 'h'){
+ usage(argv[0]);
+ exit(0);
+ }
+
+ //WE NOW WILL HANDLE THE REQUIRED OPERATIONS
+
+ //TODO: #2 Document the purpose of the if statement below
+ // The if statement below is to make sure the user
+ // uses a command with at least 1 flag and 2 required
+ // arguments to proceed. Otherwise, an error will
+ // occur and the syntax will be provided to help them
+ // enter the correct command
+
+ if (argc < 3){
+ usage(argv[0]);
+ exit(1);
+ }
+
+ input_string = argv[2]; //capture the user input string
+
+ //TODO: #3 Allocate space for the buffer using malloc and
+ // handle error if malloc fails by exiting with a
+ // return code of 99
+ // CODE GOES HERE FOR #3
+ buff = malloc(sizeof(char)*BUFFER_SZ);
+
+
+ user_str_len = setup_buff(buff, input_string, BUFFER_SZ); //see todos
+
+
+ if (user_str_len < 0){
+ printf("Error setting up buffer, error = %d\n", user_str_len);
+ exit(2);
+ }
+
+ switch (opt){
+ case 'c':
+ rc = count_words(buff, BUFFER_SZ, user_str_len); //you need to implement
+ if (rc < 0){
+ printf("Error counting words, rc = %d", rc);
+ exit(2);
+ }
+ printf("Word Count: %d\n", rc);
+ break;
+
+ //TODO: #5 Implement the other cases for 'r' and 'w' by extending
+ // the case statement options
+
+ case 'w':
+ wordPrint(buff, user_str_len);
+ break;
+
+ case 'r':
+ reverse(buff, user_str_len);
+ break;
+
+ case 'x':
+ if (argc < 5) {
+ printf("Not Implemented!\n");
+ exit(1);
+ }
+
+ char *word = argv[3]; // word to replace
+ char *replacement = argv[4];
+
+ char *dest = malloc(sizeof(char) * 50);
+
+ int destLenght = replace(buff, word, replacement, dest, BUFFER_SZ);
+ if (destLenght == -1) {
+ printf("Not implemented! Replacement is causing buffer overflow.\n");
+ exit(2); // overflow error
+ }
+
+ if (destLenght == 1) {
+ printf("Not implemented! Word not found.\n");
+ exit(3); // error with provided service
+ }
+
+ user_str_len = setup_buff(buff, dest, BUFFER_SZ);
+ free(dest);
+
+ break;
+
+ default:
+ usage(argv[0]);
+ exit(1);
+ }
+
+
+ //TODO: #6 Dont forget to free your buffer before exiting
+ print_buff(buff,BUFFER_SZ);
+ free(buff);
+ exit(0);
+}
+
+//TODO: #7 Notice all of the helper functions provided in the
+// starter take both the buffer as well as the length. Why
+// do you think providing both the pointer and the length
+// is a good practice, after all we know from main() that
+// the buff variable will have exactly 50 bytes?
+//
+// Providing both the pointer and the length is necessary
+// because it will help the function keep track of the length
+// of the buffer while and after each step of modification
+// to avoid overflow as well as to set up the buffer after
+// the string operation is complete (so that it always has
+// exactly 50 bytes)
\ No newline at end of file
--
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