C PROGRAMMING PROGRAM • BASICS & INPUT/OUTPUT

Calculate Compound Interest

Learn how to calculate compound interest using a clear C program.

Intermediatepow()FormulaCompounding

PROBLEM UNDERSTANDING

Input and expected output

Sample input

10000 10 2

Sample output

Compound interest = 2100.00
Total amount = 12100.00

COMPLETE C PROGRAM

Complete C implementation

#include <stdio.h>
#include <math.h>

int main(void)
{
    double principal, rate, time, amount;

    printf("Enter principal, annual rate and time: ");
    scanf("%lf %lf %lf", &principal, &rate, &time);
    amount = principal * pow(1.0 + rate / 100.0, time);
    printf("Compound interest = %.2f\n", amount - principal);
    printf("Total amount = %.2f\n", amount);
    return 0;
}

CURRENT STEP

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SELECTED LINE

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EXPECTED OUTPUT FOR THE SAMPLE

Compound interest = 2100.00
Total amount = 12100.00

0%Step 0 of 0

PROGRAM EXPLANATION

Algorithm and explanation

Read the required input values.
Compute P(1+R/100)^T using pow(), then subtract the principal.
Display the computed result.

Compute P(1+R/100)^T using pow(), then subtract the principal.

EFFICIENCY

Time and space complexity

Time complexity

O(1)

Auxiliary space

O(1)

DEBUGGING CHECKLIST

Common mistakes

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Use the correct format specifier for every variable.

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Initialize variables before using their values.

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Check braces, semicolons and input order carefully.

Try it yourself

Practice: Run the program with the sample input, predict its output, and then test one boundary case of your own.