Tariff Calculation Program in C

A tariff program is a useful example of range-based if...else logic. This version calculates the charge by slabs so each unit range is priced separately instead of applying one rate to the entire consumption.

Example Tariff Slabs Top ↑

• First 100 units: 1.50 per unit
• Next 100 units: 2.00 per unit
• Units above 200: 3.00 per unit

Progressive Slab Calculation Top ↑

#include <stdio.h>

int main(void) {
    double units = 250.0;
    double charge;

    if (units < 0.0) {
        printf("Units cannot be negative.\n");
        return 1;
    }

    if (units <= 100.0) {
        charge = units * 1.50;
    } else if (units <= 200.0) {
        charge = 100.0 * 1.50
               + (units - 100.0) * 2.00;
    } else {
        charge = 100.0 * 1.50
               + 100.0 * 2.00
               + (units - 200.0) * 3.00;
    }

    printf("Charge = %.2f\n", charge);
    return 0;
}

Tariff from User Input Top ↑

#include <stdio.h>

int main(void) {
    double units;

    printf("Enter units consumed: ");
    if (scanf("%lf", &units) != 1 || units < 0.0) {
        printf("Enter a valid non-negative number.\n");
        return 1;
    }

    double charge;

    if (units <= 100.0) {
        charge = units * 1.50;
    } else if (units <= 200.0) {
        charge = 150.0
               + (units - 100.0) * 2.00;
    } else {
        charge = 350.0
               + (units - 200.0) * 3.00;
    }

    printf("Total charge = %.2f\n", charge);
    return 0;
}

Subhendu Mohapatra

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I write and maintain practical tutorials on Python, PHP, SQL, JavaScript, HTML, jQuery, and web development at plus2net. The tutorials focus on clear explanations, working examples, and code that readers can test and adapt while learning.

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