C Program To Find Simple Interest

Simple Interest is the interest calculated only on the original principal amount, without adding the earned interest back to the principal.

• It is calculated on the principal amount for the entire period.
• The interest earned is not added to the principal amount for future calculations.

Examples

Input: Principal = 1000, Rate = 5, Time = 2
Output: Simple Interest = 100

Input: Principal = 2000, Rate = 3.5, Time = 4
Output: Simple Interest = 280

Finding Simple Interest

To find the simple interest in the C programming language, we can directly implement the simple interest formula with the required values such as rate, time, and principal amount as input since there is no built-in C function to calculate it directly.

Simple Interest Formula

Simple Interest = Principal * Rate * Time​ / 100

#include <stdio.h>

int main() {
  
    // Input values
    float P = 1, R = 1, T = 1;

    // Calculate simple interest
    float SI = (P * T * R) / 100;

    // Print Simple Interest
    printf("Simple Interest = %f\n", SI);

    return 0;
}

Simple Interest = 0.010000

Simple Interest Calculator Using Function

We can also define a function name smpInt() that takes rate, time and principle as arguments at returns the simple interest. It is more convenient when we need to find the simple interest frequently.

#include <stdio.h>

// Function to calculate simple interest
float smpInt(float p, float r, float t) {
    return (p * r * t) / 100;
}

int main() {
        // Input values
    float P = 10000, R = 12, T = 1, SI;

   
    // Call function to calculate simple interest
    SI = smpInt(P, R, T);

    // Display the result
    printf("Simple Interest: %.2f\n", SI);

    return 0;
}