#include <stdio.h>
#include <math.h>   // for pow()
 
int main() {
    float principal, rate, emi, totalPayment, totalInterest;
    int time, n, choice;
    float monthlyRate;
 
    // Input common loan details
    printf("Enter the loan amount (Principal): ");
    scanf("%f", &principal);
 
    printf("Enter annual rate of interest (in %%): ");
    scanf("%f", &rate);
 
    printf("Enter loan tenure (in years): ");
    scanf("%d", &time);
 
    // Convert tenure into months
    n = time * 12;
    // Convert annual interest rate to monthly rate
    monthlyRate = rate / (12 * 100);
 
    // Calculate EMI using formula
    emi = (principal * monthlyRate * pow(1 + monthlyRate, n)) /
          (pow(1 + monthlyRate, n) - 1);
 
    // Calculate total payment and interest
    totalPayment = emi * n;
    totalInterest = totalPayment - principal;
 
    do {
        // Display menu
        printf("\n===== Loan Calculator Menu =====\n");
        printf("1. Calculate EMI\n");
        printf("2. Calculate Total Payment\n");
        printf("3. Calculate Total Interest\n");
        printf("4. Show Full Loan Details\n");
        printf("5. Exit\n");
        printf("Enter your choice: ");
        scanf("%d", &choice);
 
        switch(choice) {
            case 1:
                printf("Monthly EMI: %.2f\n", emi);
                break;
            case 2:
                printf("Total Payment (Principal + Interest): %.2f\n", totalPayment);
                break;
            case 3:
                printf("Total Interest Paid: %.2f\n", totalInterest);
                break;
            case 4:
                printf("\nLoan Amount: %.2f", principal);
                printf("\nAnnual Interest Rate: %.2f%%", rate);
                printf("\nTenure: %d years (%d months)", time, n);
                printf("\nMonthly EMI: %.2f", emi);
                printf("\nTotal Payment: %.2f", totalPayment);
                printf("\nTotal Interest: %.2f\n", totalInterest);
                break;
            case 5:
                printf("Exiting program. Goodbye!\n");
                break;
            default:
                printf("Invalid choice! Please enter 1–5.\n");
        }
 
    } while(choice != 5);
 
    return 0;
}