Inequalities, Bounds, and Constraints

/**
 * Fintech Math Bootcamp · Lesson 008 of 120
 * Inequalities, Bounds, and Constraints
 * Module 01: Mathematical Language and Quantitative Reasoning
 *
 * Scenario: A lending limit that is a constraint, not an opinion
 * Rule:     0 ≤ exposure ≤ limit
 *
 * Try it:   Is 1,000 accepted by exposure < 1,000?
 *
 * Lesson article: https://thefintechbuilder.com/financial-mathematics-statistics-and-data-foundations/mathematical-language-and-quantitative-reasoning/inequalities-bounds-and-constraints/
 * Free course:    https://courses.thefintechbuilder.com
 * Synthetic teaching example, not financial advice or a production library.
 */

export function lesson008() {
  const limit = 1000;
  const requests = [-10, 0, 800, 1000, 1200];
  const result = requests.map(x => ({
    amount: x,
    allowed: Number.isFinite(x) && x >= 0 && x <= limit
  }));
  return result;
}

export const checkedResult = [{"amount":-10,"allowed":false},{"amount":0,"allowed":true},{"amount":800,"allowed":true},{"amount":1000,"allowed":true},{"amount":1200,"allowed":false}];

// Run this file directly: npx tsx lessons/01-mathematical-language-and-quantitative-reasoning/008-inequalities-bounds-and-constraints.ts
if (process.argv[1] && import.meta.url.endsWith(process.argv[1].replace(/\\/g, "/").split("/").pop()!)) {
  console.log(JSON.stringify(lesson008(), null, 2));
}

"""
Fintech Math Bootcamp · Lesson 008 of 120
Inequalities, Bounds, and Constraints
Module 01: Mathematical Language and Quantitative Reasoning

Scenario: A lending limit that is a constraint, not an opinion
Rule:     0 ≤ exposure ≤ limit

Try it:   Is 1,000 accepted by exposure < 1,000?

Lesson article: https://thefintechbuilder.com/financial-mathematics-statistics-and-data-foundations/mathematical-language-and-quantitative-reasoning/inequalities-bounds-and-constraints/
Free course:    https://courses.thefintechbuilder.com
Synthetic teaching example, not financial advice or a production library.

Run it: python main.py
"""

import json
import math


def lesson008() -> list:
    limit = 1000
    requests = [-10, 0, 800, 1000, 1200]
    result = [
        {"amount": x, "allowed": math.isfinite(x) and 0 <= x <= limit}
        for x in requests
    ]
    return result


if __name__ == "__main__":
    print(json.dumps(lesson008(), indent=2))

/**
 * Fintech Math Bootcamp · Lesson 008 of 120
 * Inequalities, Bounds, and Constraints
 * Module 01: Mathematical Language and Quantitative Reasoning
 *
 * Scenario: A lending limit that is a constraint, not an opinion
 * Rule:     0 ≤ exposure ≤ limit
 *
 * Try it:   Is 1,000 accepted by exposure < 1,000?
 *
 * Lesson article: https://thefintechbuilder.com/financial-mathematics-statistics-and-data-foundations/mathematical-language-and-quantitative-reasoning/inequalities-bounds-and-constraints/
 * Free course:    https://courses.thefintechbuilder.com
 * Synthetic teaching example, not financial advice or a production library.
 *
 * Run it: javac Main.java && java Main
 */

import java.util.ArrayList;
import java.util.List;

public class Main {
    static final class LimitCheck {
        final double amount;
        final boolean allowed;

        LimitCheck(double amount, boolean allowed) {
            this.amount = amount;
            this.allowed = allowed;
        }
    }

    static List<LimitCheck> lesson008() {
        double limit = 1000;
        double[] requests = {-10, 0, 800, 1000, 1200};
        List<LimitCheck> result = new ArrayList<LimitCheck>();
        for (double x : requests) {
            result.add(new LimitCheck(x, Double.isFinite(x) && x >= 0 && x <= limit));
        }
        return result;
    }

    public static void main(String[] args) {
        List<String> items = new ArrayList<String>();
        for (LimitCheck check : lesson008()) {
            items.add(object("amount", num(check.amount), "allowed", String.valueOf(check.allowed)));
        }
        System.out.println(array(items));
    }

    // Formats a double the way JSON.stringify does: whole numbers without ".0", null for NaN or infinity.
    static String num(double x) {
        if (Double.isNaN(x) || Double.isInfinite(x)) return "null";
        if (x == Math.rint(x) && Math.abs(x) < 1e15) return String.valueOf((long) x);
        return String.valueOf(x);
    }

    static String quote(String text) {
        return "\"" + text.replace("\\", "\\\\").replace("\"", "\\\"") + "\"";
    }

    // Indents an already formatted JSON value by one level.
    static String nested(String json) {
        return json.replace("\n", "\n  ");
    }

    static String object(String... keysAndValues) {
        if (keysAndValues.length == 0) return "{}";
        StringBuilder out = new StringBuilder("{");
        for (int i = 0; i < keysAndValues.length; i += 2) {
            out.append(i == 0 ? "\n  " : ",\n  ")
               .append(quote(keysAndValues[i])).append(": ").append(nested(keysAndValues[i + 1]));
        }
        return out.append("\n}").toString();
    }

    static String array(java.util.List<String> items) {
        if (items.isEmpty()) return "[]";
        StringBuilder out = new StringBuilder("[");
        for (int i = 0; i < items.size(); i++) {
            out.append(i == 0 ? "\n  " : ",\n  ").append(nested(items.get(i)));
        }
        return out.append("\n]").toString();
    }
}

// Fintech Math Bootcamp · Lesson 008 of 120
// Inequalities, Bounds, and Constraints
// Module 01: Mathematical Language and Quantitative Reasoning
//
// Scenario: A lending limit that is a constraint, not an opinion
// Rule:     0 ≤ exposure ≤ limit
//
// Try it:   Is 1,000 accepted by exposure < 1,000?
//
// Lesson article: https://thefintechbuilder.com/financial-mathematics-statistics-and-data-foundations/mathematical-language-and-quantitative-reasoning/inequalities-bounds-and-constraints/
// Free course:    https://courses.thefintechbuilder.com
// Synthetic teaching example, not financial advice or a production library.
//
// Run it: go run main.go

package main

import (
	"encoding/json"
	"fmt"
	"math"
)

type LimitCheck struct {
	Amount  float64 `json:"amount"`
	Allowed bool    `json:"allowed"`
}

func lesson008() []LimitCheck {
	limit := 1000.0
	requests := []float64{-10, 0, 800, 1000, 1200}
	result := make([]LimitCheck, 0, len(requests))
	for _, x := range requests {
		result = append(result, LimitCheck{
			Amount:  x,
			Allowed: !math.IsNaN(x) && !math.IsInf(x, 0) && x >= 0 && x <= limit,
		})
	}
	return result
}

func main() {
	printJSON(lesson008())
}

// printJSON prints a value as JSON indented with two spaces, like JSON.stringify(value, null, 2).
func printJSON(value any) {
	out, err := json.MarshalIndent(value, "", "  ")
	if err != nil {
		panic(err)
	}
	fmt.Println(string(out))
}

/**
 * Fintech Math Bootcamp · Lesson 008 of 120
 * Inequalities, Bounds, and Constraints
 * Module 01: Mathematical Language and Quantitative Reasoning
 *
 * Scenario: A lending limit that is a constraint, not an opinion
 * Rule:     0 ≤ exposure ≤ limit
 *
 * Try it:   Is 1,000 accepted by exposure < 1,000?
 *
 * Lesson article: https://thefintechbuilder.com/financial-mathematics-statistics-and-data-foundations/mathematical-language-and-quantitative-reasoning/inequalities-bounds-and-constraints/
 * Free course:    https://courses.thefintechbuilder.com
 * Synthetic teaching example, not financial advice or a production library.
 *
 * Run it: g++ -std=c++17 -o main main.cpp && ./main
 */

#include <charconv>
#include <cmath>
#include <iostream>
#include <string>
#include <utility>
#include <vector>

// Formats a double the way JSON.stringify does: shortest round-trip form, null for NaN or infinity.
std::string num(double x) {
    if (!std::isfinite(x)) return "null";
    char buffer[32];
    auto [end, error] = std::to_chars(buffer, buffer + sizeof buffer, x);
    (void)error;
    return std::string(buffer, end);
}

std::string quote(const std::string& text) {
    std::string out = "\"";
    for (char c : text) {
        if (c == '"' || c == '\\') out += '\\';
        out += c;
    }
    return out + "\"";
}

// Indents an already formatted JSON value by one level.
std::string nested(const std::string& json) {
    std::string out;
    for (char c : json) {
        out += c;
        if (c == '\n') out += "  ";
    }
    return out;
}

std::string object(const std::vector<std::pair<std::string, std::string>>& fields) {
    if (fields.empty()) return "{}";
    std::string out = "{";
    for (std::size_t i = 0; i < fields.size(); ++i) {
        out += i == 0 ? "\n  " : ",\n  ";
        out += quote(fields[i].first) + ": " + nested(fields[i].second);
    }
    return out + "\n}";
}

std::string array(const std::vector<std::string>& items) {
    if (items.empty()) return "[]";
    std::string out = "[";
    for (std::size_t i = 0; i < items.size(); ++i) {
        out += i == 0 ? "\n  " : ",\n  ";
        out += nested(items[i]);
    }
    return out + "\n]";
}

struct LimitCheck {
    double amount;
    bool allowed;
};

std::vector<LimitCheck> lesson008() {
    const double limit = 1000;
    const std::vector<double> requests{-10, 0, 800, 1000, 1200};
    std::vector<LimitCheck> result;
    for (double x : requests) {
        result.push_back({x, std::isfinite(x) && x >= 0 && x <= limit});
    }
    return result;
}

int main() {
    std::vector<std::string> items;
    for (const LimitCheck& check : lesson008()) {
        items.push_back(object({
            {"amount", num(check.amount)},
            {"allowed", check.allowed ? "true" : "false"}
        }));
    }
    std::cout << array(items) << "\n";
}

//! Fintech Math Bootcamp · Lesson 008 of 120
//! Inequalities, Bounds, and Constraints
//! Module 01: Mathematical Language and Quantitative Reasoning
//!
//! Scenario: A lending limit that is a constraint, not an opinion
//! Rule:     0 ≤ exposure ≤ limit
//!
//! Try it:   Is 1,000 accepted by exposure < 1,000?
//!
//! Lesson article: https://thefintechbuilder.com/financial-mathematics-statistics-and-data-foundations/mathematical-language-and-quantitative-reasoning/inequalities-bounds-and-constraints/
//! Free course:    https://courses.thefintechbuilder.com
//! Synthetic teaching example, not financial advice or a production library.
//!
//! Run it: rustc main.rs && ./main

struct LimitCheck {
    amount: f64,
    allowed: bool,
}

fn lesson008() -> Vec<LimitCheck> {
    let limit = 1000.0;
    let requests = [-10.0, 0.0, 800.0, 1000.0, 1200.0];
    let result: Vec<LimitCheck> = requests
        .iter()
        .map(|&x| LimitCheck {
            amount: x,
            allowed: x.is_finite() && x >= 0.0 && x <= limit,
        })
        .collect();
    result
}

fn main() {
    let items: Vec<String> = lesson008()
        .iter()
        .map(|check| {
            object(&[
                ("amount", num(check.amount)),
                ("allowed", check.allowed.to_string()),
            ])
        })
        .collect();
    println!("{}", array(&items));
}

/// Formats a number the way JSON.stringify does: shortest round-trip form, null for NaN or infinity.
fn num(x: f64) -> String {
    if x.is_finite() {
        format!("{}", x)
    } else {
        "null".to_string()
    }
}

fn quote(text: &str) -> String {
    format!("\"{}\"", text.replace('\\', "\\\\").replace('"', "\\\""))
}

/// Indents an already formatted JSON value by one level.
fn nested(json: &str) -> String {
    json.replace('\n', "\n  ")
}

fn object(fields: &[(&str, String)]) -> String {
    if fields.is_empty() {
        return "{}".to_string();
    }
    let lines: Vec<String> = fields
        .iter()
        .map(|(key, value)| format!("  {}: {}", quote(key), nested(value)))
        .collect();
    format!("{{\n{}\n}}", lines.join(",\n"))
}

fn array(items: &[String]) -> String {
    if items.is_empty() {
        return "[]".to_string();
    }
    let lines: Vec<String> = items.iter().map(|item| format!("  {}", nested(item))).collect();
    format!("[\n{}\n]", lines.join(",\n"))
}

/**
 * Fintech Math Bootcamp · Lesson 008 of 120
 * Inequalities, Bounds, and Constraints
 * Module 01: Mathematical Language and Quantitative Reasoning
 *
 * Scenario: A lending limit that is a constraint, not an opinion
 * Rule:     0 ≤ exposure ≤ limit
 *
 * Try it:   Is 1,000 accepted by exposure < 1,000?
 *
 * Lesson article: https://thefintechbuilder.com/financial-mathematics-statistics-and-data-foundations/mathematical-language-and-quantitative-reasoning/inequalities-bounds-and-constraints/
 * Free course:    https://courses.thefintechbuilder.com
 * Synthetic teaching example, not financial advice or a production library.
 *
 * Run it: dotnet run  (inside a console project that holds this Program.cs)
 */

using System.Text.Json;

var jsonOptions = new JsonSerializerOptions { WriteIndented = true, PropertyNamingPolicy = JsonNamingPolicy.CamelCase };
Console.WriteLine(JsonSerializer.Serialize(Lesson008(), jsonOptions));

static List<LimitCheck> Lesson008()
{
    const double limit = 1000;
    double[] requests = { -10, 0, 800, 1000, 1200 };
    var result = requests
        .Select(x => new LimitCheck(x, double.IsFinite(x) && x >= 0 && x <= limit))
        .ToList();
    return result;
}

record LimitCheck(double Amount, bool Allowed);