16. Calculate Gross Salary | Conditional Statements

📋 Problem Statement

Given the basic salary of an employee, calculate its gross salary according to the following conditions:

Basic Salary Range	HRA (House Rent Allowance)	DA (Dearness Allowance)
Basic Salary ≤ 10000	20% of basic	80% of basic
Basic Salary ≤ 20000	25% of basic	90% of basic
Basic Salary > 20000	30% of basic	95% of basic

Formula: Gross Salary = Basic Salary + HRA + DA

📥 Input Format

Enter an integer indicating the basic salary as input

📤 Output Format

Print the output as floating point value (2 decimal places) indicating the gross salary
Format: Rs.XXXXX.XX

💡 Examples

Example 1:

Input: 10000

Output: Rs.20000.00

Calculation:
Basic = 10000 (≤ 10000)
HRA = 10000 × 0.2 = 2000
DA = 10000 × 0.8 = 8000
Gross = 10000 + 2000 + 8000 = 20000.00

Example 2:

Input: 35000

Output: Rs.78750.00

Calculation:
Basic = 35000 (> 20000)
HRA = 35000 × 0.3 = 10500
DA = 35000 × 0.95 = 33250
Gross = 35000 + 10500 + 33250 = 78750.00

Example 3:

Input: 25468

Output: Rs.57303.00

Calculation:
Basic = 25468 (> 20000)
HRA = 25468 × 0.3 = 7640.4
DA = 25468 × 0.95 = 24194.6
Gross = 25468 + 7640.4 + 24194.6 = 57303.00

⚠️ Constraints

-10^9 <= INPUT <= 10^9

✅ Solution

#include <iostream>
#include <iomanip>

using namespace std;

int main() {
    long long basic;
    long double gross;
    cin >> basic;
    
    if (basic <= 10000)
        gross = basic + basic * 0.2 + basic * 0.8;
    else if (basic <= 20000 && basic > 10000)
        gross = basic + basic * 0.25 + basic * 0.9;
    else if (basic > 20000)
        gross = basic + basic * 0.3 + basic * 0.95;
    
    cout << fixed << setprecision(2) << "Rs." << gross;
    
    return 0;
}

🔑 Key Concepts

Else-if Ladder: Multiple mutually exclusive conditions for different salary ranges
Long Long Data Type: Used for basic salary to handle large input values up to 10^9
Long Double: For gross salary to maintain precision in percentage calculations
iomanip Library: fixed and setprecision(2) for 2 decimal places
Percentage Calculations: Converting percentages to decimals (20% = 0.2, 80% = 0.8)
Real-world Application: Salary calculation systems in payroll management

⚠️ Common Mistakes to Avoid

Integer Division: Don't use int for calculations involving percentages - precision will be lost
Missing setprecision: Without it, output won't have exactly 2 decimal places
Wrong Condition Order: Check smaller ranges first, then larger ones
Redundant Conditions: The && basic > 10000 in second condition is actually redundant due to else-if logic
Forgetting 'Rs.' Prefix: Output format specifically requires "Rs." before the amount

🎯 What You'll Learn

How to structure else-if ladders for range-based conditions
Working with floating-point precision in financial calculations
Choosing appropriate data types for large numbers and precise decimals
Using iomanip library for formatted output
Applying percentage calculations in real-world scenarios
Understanding payroll calculation logic

Calculate Gross Salary of Employee