C++: Count Occurrences of Double Values in a Map

Here is an example code that converts an array of double values to a map with value counts in C++:

#include <iostream>
#include <map>

int main() {
    double arr[] = {1.2, 3.4, 4.5, 1.2, 2.3, 4.5, 1.2, 3.4};
    int n = sizeof(arr) / sizeof(arr[0]);

    std::map<double, int> value_counts;
    for (int i = 0; i < n; i++) {
        if (value_counts.find(arr[i]) == value_counts.end()) {
            value_counts[arr[i]] = 1;
        } else {
            value_counts[arr[i]]++;
        }
    }

    for (auto it = value_counts.begin(); it != value_counts.end(); it++) {
        std::cout << it->first << ': ' << it->second << std::endl;
    }

    return 0;
}

In this code, we first define an array 'arr' of double values and determine its length 'n'. We then create an empty map 'value_counts' with keys of type 'double' and values of type 'int'.

We loop through the array 'arr', and for each value, we check if it already exists in the map by using the 'find' function. If it doesn't exist, we add it to the map with a count of 1. If it does exist, we increment its count by 1.

Finally, we loop through the map and print out each key-value pair, where the key is the double value and the value is its count.