adding cs142 code

cs142/lab09/io.cpp

@@ -0,0 +1,30 @@
+#include <string>
+#include <fstream>
+#include <streambuf>
+#include <stdexcept>
+using namespace std;
+
+#include "jsoncpp/json/json.h"
+#include "io.h"
+#include "restaurant.h"
+
+vector<restaurant> parse_file(string filename) {
+    vector<restaurant> restaurants;
+    ifstream infile(filename.c_str());
+    string file_contents((istreambuf_iterator<char>(infile)),
+                                 istreambuf_iterator<char>());
+    Json::Value root;
+    Json::Reader reader;
+    bool good_parse = reader.parse(file_contents, root);
+    if(not good_parse) {
+        throw runtime_error(reader.getFormattedErrorMessages());
+    }
+    for(unsigned int i = 0; i < root.size(); i++) {
+        string name = root[i]["name"].asString();
+        int score = root[i]["score"].asInt();
+        restaurant r(name, score);
+        restaurants.push_back(r);
+    }
+
+    return restaurants;
+}