Example: Income Tax Calculator in C

// Income Tax Calculator
#include <stdio.h>

int main() {
    double annual_income;
    double income_tax = 0.0; // Initialize tax to 0

    // Step 1: Prompt user for annual income
    printf("Enter your annual taxable income (in PKR): ");
    scanf("%lf", &annual_income);

    // Step 2: Calculate income tax based on illustrative FBR-like slabs
    if (annual_income <= 600000) {
        income_tax = 0.0; // No tax for income up to 600,000
    } else if (annual_income <= 1200000) {
        // Tax 2.5% on amount exceeding 600,000
        income_tax = (annual_income - 600000) * 0.025;
    } else if (annual_income <= 1800000) {
        // Fixed tax for previous slab (600,000 * 2.5% = 15,000)
        // Plus 12.5% on amount exceeding 1,200,000
        income_tax = 15000 + (annual_income - 1200000) * 0.125;
    } else if (annual_income <= 2500000) {
        // Fixed tax for previous slabs:
        // (600,000 * 2.5%) + (600,000 * 12.5%) = 15,000 + 75,000 = 90,000
        // Plus 20% on amount exceeding 1,800,000
        income_tax = 90000 + (annual_income - 1800000) * 0.20;
    } else { // Income > 2,500,000
        // Fixed tax for previous slabs:
        // 90,000 + (700,000 * 20%) = 90,000 + 140,000 = 230,000
        // Plus 25% on amount exceeding 2,500,000
        income_tax = 230000 + (annual_income - 2500000) * 0.25;
    }

    // Step 3: Display the calculated income tax
    printf("Annual Taxable Income: PKR %.2lf\n", annual_income);
    printf("Calculated Income Tax: PKR %.2lf\n", income_tax);

    return 0;
}