Read n value
Initialize count 0
for i 1 to n
for j 1 to i
if i mod j is equal to 0
then increment count
then print count.

#include<stdio.h>
 
int main()
{
int i, j, n, count=0;
 
printf("Enter the limit:");
scanf("%d", &n);
printf("The limit numbers are:\n");
for(i=1;i<=n;i++)
{
 for(j=1;j<=i;j++)
 {
    if(i%j==0)
    {
    count++;
    }
      
 } 
 printf("%d\n", count);
}
return 0;
}

Read the number of terms n
Initialize a = 0, b = 1 
print a and b values
for i = 3 to n
increment the i value
c = a+b
print c value
a = b
b = c

#include<stdio.h>
int main()
{
int a=0,b=1,c,n,i;
printf("Enter no. of terms:");
scanf("%d", &n);
printf("The Fibonacci sequence is:");
printf("%d%d", a,b);
for(i=3;i<=n;i++)
{
c=a+b;
printf("%d",c);
a=b;
b=c;
}
return 0;
getchar();
}

Read the number n
Initialize sum = 0
while n > 0
d = n%10
sum = sum+d
n = n/10
print sum

#include<stdio.h>
int main()
{
int n, sum=0,d;
printf("Enter any integer:");
scanf("%d", &n);
while(n>0)
{
d=n%10;
sum=sum+d;
n=n/10;
}
printf("sum of individual digits is: %d",sum);
return 0;
}