started working on simple config file parser

io.cpp

@@ -0,0 +1,40 @@
+#include <unordered_map>
+#include <string>
+#include <cstdio>
+#include <iostream>
+#include <fstream>
+
+int main()
+{
+    std::unordered_map<std::string,std::string> dictionary;
+    std::string file_name = "phigrape.conf";
+    std::ifstream file(file_name);
+    if (!file.good()) {
+        std::cout << "Not found!" << std::endl;
+        exit(1);
+    }
+    std::string str;
+    int line_number = 0;
+    while (std::getline(file, str)) {
+        line_number++;
+        auto pos = str.find('#');
+        if (pos != std::string::npos) str = str.substr(0, pos);
+        pos = str.find_first_not_of(" \t");
+        if (pos != std::string::npos) str = str.substr(pos, str.size());
+        else continue;
+        pos = str.find_last_not_of(" \t");
+        if (pos != std::string::npos) str = str.substr(0, pos+1);
+        if (str.size() == 0) continue;
+        pos = str.find_first_of(" \t");
+        if (pos == std::string::npos) {
+            std::cerr << "Error: expected a key-value pair in line " << line_number << " of file " << file_name << std::endl;
+            exit(1);
+        }
+        std::string key = str.substr(0, pos);
+        pos = str.find_first_not_of(" \t", pos+1);
+        std::string val = str.substr(pos, str.size());
+        dictionary[key] = val;
+    }
+
+    printf("dictionary[\"more\"] = %s\n", dictionary["eps"].c_str());
+}