31.Prime number checking :—
#include<stdio.h>
int main()
{
int i,n,r,count;
printf("enter a value of n ");
scanf("%d",&n);
count=0;
for(i=1;i<=n;i++)
{
r=n%i;
if(r==0)
{
count++;
}
}
if(count==2)
{
printf("It is a prime number");
}
else
{
printf("It is not a prime number");
}
return 0;
}
30.Count total number of factors :—
#include<stdio.h>
int main()
{
int i,n,r,count;
printf("enter a value of n ");
scanf("%d",&n);
count=0;
for(i=1;i<=n;i++)
{
r=n%i;
if(r==0)
{
count++;
}
}
printf("%d",count);
return 0;
}
29. Print all factors of a number :—
#include<stdio.h>
int main()
{
int i,n,r;
printf("enter a value of n ");
scanf("%d",&n);
for(i=1;i<=n;i++)
{
r=n%i;
if(r==0)
{
printf("%d",i);
}
}
return 0;
}
28. Armstrong number checking :—
#include<stdio.h>
int main()
{
int i,n,m,k,r,sum;
printf("enter value of n ");
scanf("%d",&n);
m=n;
k=0;
while(n>0)
{
n=n/10;
k++;
}
n=m;
sum=0;
while(n>0)
{
r=n%10;
n=n/10;
sum=sum+pow(r,k);
}
if(sum==m)
{
printf("It is an Armstrong number");
}
else
{
printf("It is not an Armstrong number");
}
return 0;
}
27. Count the total number of digits :—
#include<stdio.h>
int main()
{
int i,n,count;
printf("enter value of n ");
scanf("%d",&n);
count=0;
while(n>0)
{
n=n/10;
count++;
}
printf("%d",count);
return 0;
}
26. Sum of digits :—
#include<stdio.h>
int main()
{
int i,n,r,k,sum;
printf("enter value of n ");
scanf("%d",&n);
sum=0,k=n;
while(n>0)
{
r=n%10;
n=n/10;
sum=sum+r;
}
printf("%d",sum);
return 0;
}
25. (a²/2!)+(a⁴/4!)+(a⁶/6!)+... :—
#include<stdio.h>
int main()
{
int i,n,a,f,k,sum;
printf("enter value of n and a ");
scanf("%d%d",&n,&a);
sum=0,f=1;
for(i=1;i<=n;i++)
{
k=2*i;
sum=sum+pow(a,k)/(float)f;
f=f*(k+1)*(k+2);
}
printf("%d",sum);
return 0;
}
24. a+(a³/3!)+(a⁵/5!)+... :—
#include<stdio.h>
int main()
{
int i,n,a,f,k,sum;
printf("enter value of n and a ");
scanf("%d%d",&n,&a);
sum=0,f=1;
for(i=1;i<=n;i++)
{
k=2*i-1;
sum=sum+pow(a,k)/(float)f;
f=f*(k+1)*(k+2);
}
printf("%d",sum);
return 0;
}
23.a-(a²/2!)+(a³/3!)-(a⁴/4!)... :—
#include<stdio.h>
int main()
{
int i,n,a,f,s,sum;
printf("enter value of n and a ");
scanf("%d%d",&n,&a);
sum=0,f=1,s=-1;
for(i=1;i<=n;i++)
{
f=f*i;
s=s*-1;
sum=sum+pow(a,i)*s/(float)f;
}
printf("%d",sum);
return 0;
}
22. (a/1!)+(a²/2!)+(a³/3!)+(a⁴/4!)+... :—
#include<stdio.h>
int main()
{
int i,n,a,f,sum;
printf("enter value of n and a ");
scanf("%d%d",&n,&a);
sum=0,f=1;
for(i=1;i<=n;i++)
{
f=f*i;
sum=sum+pow(a,i)/(float)f;
}
printf("%d",sum);
return 0;
}
20. a-a²+a³-a⁴... :—
#include<stdio.h>
int main()
{
int i,n,a,s,sum;
printf("enter value of n and a ");
scanf("%d%d",&n,&a);
sum=0,s=-1;
for(i=1;i<=n;i++)
{
s=s*-1;
sum=sum+pow(a,i)*s;
}
printf("%d",sum);
return 0;
}
19. a+a²+a³+a⁴+a⁵... :—
#include<stdio.h>
int main()
{
int i,n,a,sum;
printf("enter value of n and a ");
scanf("%d%d",&n,&a);
sum=0;
for(i=1;i<=n;i++)
{
sum=sum+pow(a,i);
}
printf("%d",sum);
return 0;
}
18.1!-2!+3!-4!+...n :—
#include<stdio.h>
int main()
{
int i,f,n,s,sum;
printf("enter a value of n ");
scanf("%d",&n);
sum=0,f=1,s=-1;
for(i=1;i<=n;i++)
{
s=s*-1;
f=f*i;
sum=sum+f*s;
}
printf("%d",sum);
return 0;
}
17. 1!+2!+3!+...n :—
#include<stdio.h>
int main()
{
int i,f,n,sum;
printf("enter a value of n ");
scanf("%d",&n);
sum=0,f=1;
for(i=1;i<=n;i++)
{
f=f*i;
sum=sum+f;
}
printf("%d",sum);
return 0;
}
16. Input a number and check it is palindrome or not :—
#include<stdio.h>
int main()
{
int r,n,k,rev;
printf("enter a number ");
scanf("%d",&n);
k=n;
rev=0;
while(k>0)
{
r=k%10;
k=k/10;
rev=rev*10+r;
}
if(n==rev)
{
printf("%d is a palindrome",n);
}
else
{
printf("%d is not a palindrome",n);
}
return 0;
}