# Simple Interest Program in C

Simple interest is essentially a calculation of the interest a bank will charge a customer or itself on a certain principal amount over a specific period of time.

The formula for calculating the Simple Interest is given by

`Simple Interest=(P*T*R)/100`

Where,

• P is known as the principal amount.
• T is known as the time period.
• R is known as the rate of interest for the respective amount and the time Period.

There are different techniques used for implementation of the Simple Interest in C programming. They are as follows.

1. General method using main() only.
2. Using for Loop.
3. Using while Loop.
4. Using do-while Loop.
5. Using Functions.
6. Using Pointers.

### Simple Interest implementation in C Using main() Method

```// A Simple Interest Programme Using Given Values// A Simple Interest Programme Using Given Values in C
#include <stdio.h>
int main()
{
float P,T,R,Simple_Interest;
// `P` = Principal, `T` = Time period, and `R` = Rate of Interest
// `Simple_Interest` = Value of Interest
printf("Enter the Principal amount : ");
scanf("%f",&P);
printf("Enter the Time period: ");
scanf("%f",&T);
printf("Enter the rate of Interest: ");
scanf("%f",&R);
// It will determine the simple interest
Simple_Interest = (P* T * R) / 100;
// Final output is obtained
printf("\nSimple_Interest = %.2f\n", Simple_Interest);
return 0;
}
```

OUTPUT:

### Simple Interest implementation in C Using For Loop Method:

```// A simple interest programme in C that makes use of a for loop
#include <stdio.h>
int main() {
float a = 1, b, Simple_Interest;
// `Simple_Interest` = Value of Interest
printf("Enter the Principal,Time Period, and Rate of Interest::\n");
for (int count = 1; count <= 3; count++)
{
scanf("%f", &b);
// It will determines the simple Interest
a *= b;
if (count == 3)
Simple_Interest = a/100;
}
// Final Output is obtained
printf("\nSimple_Interest = %.2f\n", Simple_Interest);
return 0;
}
```

OUTPUT:

### Simple Interest implementation in C Using While Loop Method:

```// A simple interest programme in C that makes use of a While loop
#include <stdio.h>
int main()
{
float a = 1, b, Simple_Interest;
// `Simple_Interest` = Value of interest
printf("Enter the Principal , Time period, and Rate of Interest ::\n");
int count = 1;
while (count <= 3)
{
scanf("%f", b);
// It will determines the simple interst
a *= b;
if (count == 3)
Simple_Interest = a/100;
count++;
}
// final output is obtained
printf("\nSimple_Interest = %.2f\n", Simple_Interest);
return 0;
}
```

OUTPUT:

### Simple Interest implementation in C Using do-While Loop Method:

```// A simple interest programme in C that makes use of a do-While loop
#include <stdio.h>
int main()
{
float a = 1, b, Simple_Interest;
// `Simple_Interest` = Value of Interest
printf("Enter the Principal, Time Period, and Rate of Interest::\n");
int count = 1;
do {
scanf("%f", &b);
// It will determine the Simple Interest
a *= b;
if (count == 3)
Simple_Interest = a/100;
count++;
} while (count <= 3);
//Final output is obtained
printf("\nSimple Interest = %.2f\n", Simple_Interest);
return 0;
}
```

OUTPUT:

### Simple Interest implementation in C Using Functions Method:

```// A simple interest programme in C that makes use of a Functions
#include <stdio.h>
// This function will determine the value of simple interest
void SimpleInterest(float a, float b, float c)
{
float Simple_Interest; // Value of Interest
// It will determine the Simple Interest
Simple_Interest = (a * b * c) / 100;
// final output is obtained
printf("\nSimple Interest = %.2f\n", Simple_Interest);
}
// Driver Function
int main() {
float P, T, R;
// `P` = Principal, `T` = Time period, and `R` = Rate of Interest
printf("Enter the Principal, Time Period, and Rate of Interest::\n");
scanf("%f%f%f", &P, &T, &R);
SimpleInterest(P, T, R);
return 0;
}
```

OUTPUT:

### Simple Interest implementation in C Using Pointers Method:

```// A simple interest programme in C that makes use of a Pointers
#include <stdio.h>
int main()
{
float P, T, R, Simple_Interest;
// `P` = Principal, `T` = Time Period, and `R` = Rate of Interest
// `Simple_Interest` = Value of simple Interest
float *a, *b, *c; // Declartion of the pointer variables
printf("Enter the Principal, Time Period, and Rate of Interest::\n");
scanf("%f%f%f", &P, &T, &R);
a = &P;
b = &T;
c = &R;
// It will determine the Simple Interest
Simple_Interest = (*a * *b * *c) / 100;
// final output is obtained
printf("\nSimple_Interest = %.2f\n", Simple_Interest);
return 0;
}
```

OUTPUT: