Armstrong Number in C
Before going to write the c program to check whether the number is Armstrong or not, let’s understand what is Armstrong number.
Armstrong number is a number that is equal to the sum of cubes of its digits. For example 0, 1, 153, 370, 371 and 407 are the Armstrong numbers.
Let’s try to understand why 153 is an Armstrong number.
153 = (1*1*1)+(5*5*5)+(3*3*3)
where:
(1*1*1)=1
(5*5*5)=125
(3*3*3)=27
So:
1+125+27=153
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Let’s try to understand why 371 is an Armstrong number.
371 = (3*3*3)+(7*7*7)+(1*1*1)
where:
(3*3*3)=27
(7*7*7)=343
(1*1*1)=1
So:
27+343+1=371
Let’s see the c program to check Armstrong Number in C.
#include<stdio.h>
int main()
{
int n,r,sum=0,temp;
printf(“enter the number=”);
scanf(“%d”,&n);
temp=n;
while(n>0)
{
r=n%10;
sum=sum+(r*r*r);
n=n/10;
}
if(temp==sum)
printf(“armstrong number “);
else
printf(“not armstrong number”);
return 0;
}
Output:
enter the number=153
armstrong number
enter the number=5
not armstrong number
Fibonacci Series in C
Fibonacci Series in C: In case of fibonacci series, next number is the sum of previous two numbers for example 0, 1, 1, 2, 3, 5, 8, 13, 21 etc. The first two numbers of fibonacci series are 0 and 1.
There are two ways to write the fibonacci series program:
- Fibonacci Series without recursion
- Fibonacci Series using recursion
Let’s see the fibonacci series program in c without recursion.
#include<stdio.h>
int main()
{
int n1=0,n2=1,n3,i,number;
printf(“Enter the number of elements:”);
scanf(“%d”,&number);
printf(“\n%d %d”,n1,n2);//printing 0 and 1
for(i=2;i<number;++i)//loop starts from 2 because 0 and 1 are already printed
{
n3=n1+n2;
printf(” %d”,n3);
n1=n2;
n2=n3;
}
return 0;
}
Output:
Enter the number of elements:15
0 1 1 2 3 5 8 13 21 34 55 89 144 233 377
usefull code 