Upload New File

WEEK-3/stringfun.c

+#include <stdio.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <string.h>
+
+#define BUFFER_SZ 50
+
+// Prototypes
+void usage(char *);
+void print_buff(char *, int);
+int setup_buff(char *, char *, int);
+int count_words(char *, int, int);
+void reverse_string(char *, int);
+void word_print(char *, int, int);
+
+int setup_buff(char *buff, char *user_str, int len) {   //TODO: #4:  Implemented the setup buff as per the directions
+    char *b_ptr = buff;
+    char *u_ptr = user_str;
+    int user_len = 0;
+    bool last_was_space = false;
+
+    while (*u_ptr != '\0') {
+        if (user_len >= len) {
+            return -1; // Error: Input string exceeds buffer size
+        }
+
+        if (*u_ptr == ' ' || *u_ptr == '\t') {
+            if (!last_was_space) {
+                *b_ptr = ' ';
+                b_ptr++;
+                user_len++;
+                last_was_space = true;
+            }
+        } else {
+            *b_ptr = *u_ptr;
+            b_ptr++;
+            user_len++;
+            last_was_space = false;
+        }
+        u_ptr++;
+    }
+
+    while (user_len < len) {
+        *b_ptr = '.';
+        b_ptr++;
+        user_len++;
+    }
+
+    return user_len;
+}
+
+int count_words(char *buff, int len, int str_len) {
+    if (str_len > len) {
+        return -1; // Error: String length exceeds buffer size
+    }
+
+    int word_count = 0;
+    bool at_start = true;
+
+    for (int i = 0; i < str_len; i++) {
+        char c = *(buff + i);
+
+        if (at_start && c != ' ') {
+            word_count++;
+            at_start = false;
+        } else if (c == ' ') {
+            at_start = true;
+        }
+    }
+
+    return word_count;
+}
+
+void reverse_string(char *buff, int str_len) {
+    for (int i = 0, j = str_len - 1; i < j; i++, j--) {
+        char temp = *(buff + i);
+        *(buff + i) = *(buff + j);
+        *(buff + j) = temp;
+    }
+}
+
+void word_print(char *buff, int len, int str_len) {
+    printf("Word Print\n----------\n");
+    int word_start = 0;
+
+    for (int i = 0; i <= str_len; i++) {
+        if (i == str_len || *(buff + i) == ' ') {
+            printf("%.*s (%d)\n", i - word_start, buff + word_start, i - word_start);
+            word_start = i + 1;
+        }
+    }
+}
+
+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 main(int argc, char *argv[]) {
+    char *buff;
+    char *input_string;
+    char opt;
+    int rc;
+    int user_str_len;
+
+    // TODO: #1 Explain why this is safe
+    // This ensures that argv[1] exists and starts with '-'. If not, the program exits.
+    if ((argc < 2) || (*argv[1] != '-')) {
+        usage(argv[0]);
+        exit(1);
+    }
+
+    opt = (char) *(argv[1] + 1); // Get the option flag
+
+    if (opt == 'h') {
+        usage(argv[0]);
+        exit(0);
+    }
+
+    // TODO: #2 Explain the purpose of this check
+    // This ensures the user provided a string as the second argument (argv[2]).
+    if (argc < 3) {
+        usage(argv[0]);
+        exit(1);
+    }
+
+    input_string = argv[2]; // Capture user input string
+
+    // TODO: #3 Allocate buffer and handle memory allocation failure
+    buff = (char *) malloc(BUFFER_SZ);
+    if (buff == NULL) {
+        printf("Error: Memory allocation failed.\n");
+        exit(99);
+    }
+
+    user_str_len = setup_buff(buff, input_string, BUFFER_SZ);
+    if (user_str_len < 0) {
+        printf("Error setting up buffer, error = %d\n", user_str_len);
+        free(buff);
+        exit(2);
+    }
+
+    switch (opt) {
+        case 'c': // Word count
+            rc = count_words(buff, BUFFER_SZ, user_str_len);
+            if (rc < 0) {
+                printf("Error counting words, rc = %d\n", rc);
+                free(buff);
+                exit(2);
+            }
+            printf("Word Count: %d\n", rc);
+            break;
+                    //TODO:  #5 Implemented the other cases for 'r' and 'w' by extending
+                    //the case statement options
+        case 'r': // Reverse string
+            reverse_string(buff, user_str_len);
+            printf("Reversed String: %.*s\n", user_str_len, buff);
+            break;
+
+        case 'w': // Word print
+            word_print(buff, BUFFER_SZ, user_str_len);
+            break;
+        
+
+        default:
+            usage(argv[0]);
+            free(buff);
+            exit(1);
+    }
+
+    // TODO: #6 Free the buffer before exiting
+    free(buff);
+    exit(0);
+}
+
+// TODO: #7 Answer
+// Providing both the pointer and length ensures safer processing, as functions
+// cannot assume strings are null-terminated or rely on external constraints.
+// This minimizes memory-related errors.