Certainly! **Let's clarify the requirements and fix your code in C++**: --- ### **Requirements Recap:** - Use the **pthread** library. - **No global variables**. - Pass thread arguments through a **single memory location** (struct pointer). - **No code that doesn't compile**. - Code must be **modular/readable**, with **comments**. - **Multithreaded decoding** of input "rows" as implied by your sample. --- ## **Assumptions based on Input/Output** From your sample, it seems: - Each thread decodes a row. - Input format is possibly: ``` (some header lines) (symbol list) (positions to decode) ``` However, your code and test input are not totally clear. **We'll infer a reasonable row-decoding problem**. --- ## **Corrected and Improved C++ Code** Below is a proper, modular, and commented C++ pthread solution, **no globals**, **one struct per thread**, **fully readable**, and will compile. ```cpp // main.cpp #include <iostream> #include <vector> #include <string> #include <pthread.h> #include <cstring> // Structure to hold arguments for each thread struct ThreadArg { int row_num; const std::vector<char>* symbol_list; // pointer to symbols to decode from const std::vector<int>* code_list; // pointer to code positions for this row std::string decoded; // decoded output for this row }; // Thread function: decode a row void* decode_row(void* arg) { ThreadArg* t = static_cast<ThreadArg*>(arg); t->decoded.clear(); for(int pos : *(t->code_list)) { if(pos < 0 || pos >= t->symbol_list->size()) { t->decoded += '?'; // handle out-of-bounds } else { t->decoded += (*(t->symbol_list))[pos]; } } pthread_exit(nullptr); } int main() { // Modularity: Read all input first int n_rows; std::cin >> n_rows; std::vector<std::vector<int>> code_lists(n_rows); std::vector<ThreadArg> thread_args(n_rows); std::vector<pthread_t> threads(n_rows); // Read symbol list (assume next non-empty line is symbols) std::string line; std::cin.ignore(); do { std::getline(std::cin, line); } while(line.empty()); std::vector<char> symbol_list(line.begin(), line.end()); // For each row, read code positions (one line per row, space-separated ints) for(int i = 0; i < n_rows; ++i) { std::getline(std::cin, line); code_lists[i].clear(); int pos = 0; size_t idx = 0, n = line.size(); while(idx < n) { if(isdigit(line[idx])) { int val = 0; while(idx < n && isdigit(line[idx])) val = val * 10 + (line[idx++] - '0'); code_lists[i].push_back(val); } else { ++idx; } } } // Prepare and launch threads for(int i = 0; i < n_rows; ++i) { thread_args[i].row_num = i; thread_args[i].symbol_list = &symbol_list; thread_args[i].code_list = &code_lists[i]; if(pthread_create(&threads[i], nullptr, decode_row, &thread_args[i]) != 0) { std::cerr << "Error creating thread\n"; return 1; } } // Wait for all threads and print decoded rows for(int i = 0; i < n_rows; ++i) { pthread_join(threads[i], nullptr); std::cout << thread_args[i].decoded << std::endl; } return 0; } ``` --- ### **How to Use/Adapt for Your Input** - Your sample input is ambiguous, but **adjust the input reading as needed** to match your problem. - Each row is decoded in parallel without globals. - **Each thread gets a single argument struct** (single memory location per thread for passing all arguments). --- ### **Features** - **No global variables.** - **All thread arguments in a struct.** - **Thread-safe, modular, readable, and well-commented.** - **Handles out-of-bounds with '?'.** --- **If you need adjustments for your exact input format, supply a fully worked example input/output and I will tune the code for you!**