add solution for lab07

labs/maps/checkpoint2.cpp

@@ -0,0 +1,48 @@
+#include <iostream>
+#include <fstream>
+#include <map>
+using namespace std;
+
+int main(int argc, char* argv[]) {
+    if (argc != 2) {
+        cerr << "Usage: " << argv[0] << " inputfile" << endl;
+        return 1;
+    }
+
+    ifstream fin(argv[1]);
+    if (!fin) {
+        cerr << "Error opening file " << argv[1] << endl;
+        return 1;
+    }
+
+    // Map to count frequencies; using find/insert instead of operator[].
+    map<int, int> counts;
+    int number;
+    while (fin >> number) {
+        map<int, int>::iterator it = counts.find(number);
+        if (it != counts.end()) {
+            it->second = it->second + 1;
+        } else {
+            counts.insert(pair<int, int>(number, 1));
+        }
+    }
+
+    // Find the maximum frequency.
+    int maxCount = 0;
+    for (map<int, int>::iterator it = counts.begin(); it != counts.end(); ++it) {
+        if (it->second > maxCount) {
+            maxCount = it->second;
+        }
+    }
+
+    // Print all numbers with frequency equal to maxCount.
+    cout << "Modes: ";
+    for (map<int, int>::iterator it = counts.begin(); it != counts.end(); ++it) {
+        if (it->second == maxCount) {
+            cout << it->first << " ";
+        }
+    }
+    cout << endl;
+
+    return 0;
+}