# C - Exercise 3

C Programming

Share In this exercise section of the tutorial we will write some C program.

## Write a program in C to compute `(a + b)2` where the value of a and b will be provided by the user

The formula of `(a + b)2` is given below.

`(a + b)2 = a2 + b2 + 2ab`

Now we will convert this into a valid C expression.

``````Let x = (a + b)2
= a2 + b2 + 2ab
= (a * a) + (b * b) + (2 * a * b)
``````

Now we will write the code.

``````/**
* file: algebra.c
* author: yusuf shakeel
* date: 2010-12-15
* description: algebra program
*/

#include <stdio.h>
int main(void)
{
//variables
float a, b, x;

//user input
printf("Enter value of a: ");
scanf("%f", &a);

printf("Enter value of b: ");
scanf("%f", &b);

//compute
x = (a * a) + (b * b) + (2 * a * b);

//output
printf("Result = %f\n", x);

printf("End of code\n");
return 0;
}
``````

Output

``````Enter value of a: 4
Enter value of b: 2
Result = 36.000000
End of code
``````

## Write a program in C to compute `(a + b)3` where the value of a and b will be provided by the user

Try to solve this problem yourself.

Help:

``````Let x = (a + b)3
= a3 + b3 + 3a2b + 3ab2
``````

## Write a program in C to compute Simple Interest based on user input

To find Simple Interest we will need the Principal, Rate of Interest and Time.

To keep things simple we will assume Time is in years and an integer value whereas, Principal and Rate of Interest are float type.

Formula for Simple Interest is given below.

``````SI = PRT/100
= (P * R * T) / 100

where,
P = Principal
R = Rate of Interest
T = Time
``````

Now, lets write the C code.

``````/**
* file: simple-interest.c
* author: yusuf shakeel
* date: 2010-12-15
* description: simple interest program
*/

#include <stdio.h>
int main(void)
{
//variables
float si, p, r;
int t;

//user input
printf("Enter P: ");
scanf("%f", &p);

printf("Enter R: ");
scanf("%f", &r);

printf("Enter T: ");
scanf("%d", &t);

//compute
si = (p * r * t) / 100;

//output
printf("SI = %f\n", si);

printf("End of code\n");
return 0;
}
``````

Output

``````Enter P: 1000
Enter R: 10
Enter T: 2
SI = 200.000000
End of code
``````
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