w3resource

C Exercises: Calculate the sum of the series 1 +11 + 111 + 1111 + .. n terms

C For Loop: Exercise-26 with Solution

Write a program in C to find the sum of the series 1 +11 + 111 + 1111 + .. n terms.

Pictorial Presentation:

Calculate the sum of the series 1 +11 + 111 + 1111 + .. n terms

Sample Solution:

C Code:

#include <stdio.h>

void main()
{
  int n,i; 
  long sum=0;
  long int t=1;
  printf("Input the number of terms : ");
  scanf("%d",&n);
  for(i=1;i<=n;i++)
  {
     printf("%ld  ",t);
      if (i<n)
      {
          printf("+ "); 
          
      }
     sum=sum+t;
     t=(t*10)+1;
  }
  printf("\nThe Sum is : %ld\n",sum);
}

Sample Output: 

Input the number of terms : 5                                                                                 
1 + 11 + 111 + 1111 + 11111                                                                                  
The Sum is : 12345

Flowchart:

Flowchart : Calculate the sum of the series 1 +11 + 111 + 1111 + .. n terms

C Programming Code Editor:

Improve this sample solution and post your code through Disqus.

Previous: Write a program in C to display the n terms of square natural number and their sum.
Next: Write a c program to check whether a given number is a perfect number or not.

What is the difficulty level of this exercise?

Test your Programming skills with w3resource's quiz.



Share this Tutorial / Exercise on : Facebook and Twitter

C Programming: Tips of the Day

How to initialize array to 0 in C?

Global variables and static variables are automatically initialized to zero. If you have simply-

char ZEROARRAY[1024];

at global scope it will be all zeros at runtime. But actually there is a shorthand syntax if you had a local array. If an array is partially initialized, elements that are not initialized receive the value 0 of the appropriate type. You could write:

char ZEROARRAY[1024] = {0};

The compiler would fill the unwritten entries with zeros. Alternatively you could use memset to initialize the array at program startup:

Ref : https://bit.ly/3cvqplP