.
1. Find the area of a circle and area of a triangle given three sides.
/* C program to find the area of a triangle given 2 sides of triangle (using Heron's formula) and area of
circle */
#include<stdio.h>
#include<math.h>
#include<conio.h>
#define PI 3.14
int main()
{
float a, b, c, s, area; // declare variables to find area of Triangle
float radius,area_circle; // declare variables to find area of Circle
// Inputting values for triangles
printf("\nEnter three sides of triangle\n");
scanf("%f %f %f",&a,&b,&c);
// Inputting values for Circle
printf("Enter Radius of Circle(in cm): "); // take input
scanf("%f",&radius);
//Calculate area of triangle
s = (a+b+c)/2;
area = sqrt(s*(s-a)*(s-b)*(s-c));
//Area with 2 digits of precision
printf("\nArea of triangle: %.2f\n",area);
//Calculate area of Circle
area_circle = PI*radius*radius; // calculate area
printf("Area of Circle = %f cm\n",area_circle); // display result
return 0;
}
Note:
Area of Triangle with Three Sides (Heron’s Formula)
The area of a triangle with 3 sides of different measures can be calculated using Heron’s formula.
Heron’s formula includes two important steps. The first step is to find the semi perimeter of a triangle
by adding all three sides of a triangle and dividing it by 2. The next step is to apply the semi-perimeter
of triangle value in the main formula called “Heron’s Formula” to find the area of a triangle.
Area of triangles for three sides-Heron's formula where, s is semi-perimeter of the triangle = s =
(a+b+c) / 2
Output:
--------------------------------------------------------------------
2. Largest of three numbers.
/* C program to find the largest of three numbers */
#include <stdio.h>
void main()
{
int num1, num2, num3;
printf("Enter the values of num1, num2 and num3\n");
scanf("%d %d %d", &num1, &num2, &num3);
printf("num1 = %d\t num2 = %d\t num3 = %d\n", num1, num2, num3);
if (num1 > num2)
{
if (num1 > num3)
{
printf("num1 is the greatest among three \n");
}
else
{
printf("num3 is the greatest among three \n");
}
}
else if (num2 > num3)
printf("num2 is the greatest among three \n");
else
printf("num3 is the greatest among three \n");
}
Output:
--------------------------------------------------------------------
3. Reversing the digits of an integer.
/* C program to reverse a number */
#include <stdio.h>
void main
{
long num, reverse = 0, temp, remainder;
printf("Enter the number:\n");
scanf("%ld", &num);
temp = num;
while (num > 0)
{
remainder = num % 10;
reverse = reverse * 10 + remainder;
num =num/ 10;
}
printf("Given number = %ld\n", temp);
printf("Reverse of a Number is %ld\n", reverse);
}
--------------------------------------------------------------------
4. GCD of two integers.
#include <stdio.h>
void main()
{
int num1, num2, gcd, lcm, remainder, numerator, denominator;
printf("Enter two numbers\n");
scanf("%d %d", &num1, &num2);
//To find numerator and denominator
numerator = (num1>num2)?num1:num2;
denominator = (num1<num2)?num1:num2;
remainder = numerator % denominator;
while (remainder != 0)
{
numerator = denominator;
denominator = remainder;
remainder = numerator % denominator;
}
gcd = denominator;
printf("GCD of %d and %d = %d\n", num1, num2, gcd);
}
--------------------------------------------------------------------
5. Computing nth Fibonacci numbers.
#include<stdio.h>
int Fibonacci(int n)
{
if (n <= 1)
return n;
return Fibonacci(n - 1) + Fibonacci(n - 2);
}
int main()
{
int n;
printf("Enter the n value: ");
scanf("%d", &n);
printf("%d", Fibonacci(n - 1));
}
--------------------------------------------------------------------
6. Finding Even and Odd numbers.
#include <stdio.h>
void main()
{
int num1, rem1;
printf("Input an integer : ");
scanf("%d", &num1);
rem1 = num1 % 2;
if (rem1 == 0)
printf("%d is an even integer\n", num1);
else
printf("%d is an odd integer\n", num1);
}
--------------------------------------------------------------------
7. Generating prime numbers
#include<stdio.h>
void main()
{
int i, num, n, count;
printf("Enter the range: \n");
scanf("%d", &n);
printf("The prime numbers in between the range 1 to %d:",n);
for(num = 1;num<=n;num++)
{
count = 0;
for(i=2;i<=num/2;i++)
{
if(num%i==0)
{
count++;
break;
}
}
if(count==0 && num!= 1)
printf("%d ",num);
}
}
OR
#include<stdio.h>
void main ()
{
int i,j,n;
printf("Enter the Range ");
scanf("%d",&n);
for (i=1;i<=n;i++)
{
for(j=2;j<i;j++)
{
if(i%j==0)
break;
}
if(i==j)
printf("%d ",i);
}
}
--------------------------------------------------------------------
8. Exchanging the values of two variables
#include <stdio.h>
void main()
{
int x, y,temp;
printf("Enter Value of x= ");
scanf("%d", &x);
printf("\nEnter Value of y= ");
scanf("%d", &y);
temp = x;
x = y;
y = temp;
printf("\nAfter Swapping: x = %d, y = %d", x, y);
}
--------------------------------------------------------------------
9. Counting: Print number from 100 to 200 which are divisible by 7 and display their sum
and count using for loop.
#include<stdio.h>
void main()
{
int d,i,count=0,val;
printf("The numbers which are divisible by 7\nbetween 100 and 200: \n");
for(i=100;i<200;i++)
{
if(i%7==0)
{
printf("\t");
count=count+1;
val=i;
printf("%d",val);
}
}
printf("\n");
printf("count=%d",count);
}
--------------------------------------------------------------------
10. Summation of set of Numbers.
#include<stdio.h>
int main()
{
int Number, i, Sum = 0;
printf("\n Enter any Integer Value\n");
scanf("%d", &Number);
for(i = 1; i <= Number; i++)
{
Sum = Sum + i;
}
printf("Sum of Natural Numbers = %d", Sum);
return 0;
}
--------------------------------------------------------------------
11. Factorial Computation.
Factorial Program in C: Factorial of n is the product of all positive descending integers. Factorial of n
is denoted by n!. For example:
5! = 5*4*3*2*1 = 120
3! = 3*2*1 = 6
#include <stdio.h>
int main() {
int n, i;
unsigned long long fact = 1;
printf("Enter an integer: ");
scanf("%d", &n);
// shows error if the user enters a negative integer
if (n < 0)
printf("Error! Factorial of a negative number doesn't exist.");
else {
for (i = 1; i <= n; ++i) {
fact *= i;
}
printf("Factorial of %d = %llu", n, fact);
}
return 0;
}