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C Exercises: Display the sum of the series [ 9 + 99 + 999 + 9999 ...]

C For Loop: Exercise-21 with Solution

Write a program in C to display the sum of the series [ 9 + 99 + 999 + 9999 ...].

Pictorial Presentation:

Display the sum of the series [ 9 + 99 + 999 +  9999 ...]

Sample Solution:

C Code:

#include <stdio.h>

void main()
{   long int n,i,t=9;
	int sum =0;
	printf("Input the number or terms :");
	scanf("%ld",&n);
	for (i=1;i<=n;i++)
	{ sum +=t;
	  printf("%ld   ",t);
	  t=t*10+9;
	}
	printf("\nThe sum of the series = %d \n",sum);
} 

Sample Output:

Input the number or terms :5                                                                                  
9   99   999   9999   99999                                                                                   
The sum of the series = 111105  

Flowchart:

Flowchart: Display   the sum of the series [ 9 + 99 + 999 +  9999 ...]

C Programming Code Editor:

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C Programming: Tips of the Day

Printing hexadecimal characters in C:

You are seeing the ffffff because char is signed on your system. In C, vararg functions such as printf will promote all integers smaller than int to int. Since char is an integer (8-bit signed integer in your case), your chars are being promoted to int via sign-extension.

Since c0 and 80 have a leading 1-bit (and are negative as an 8-bit integer), they are being sign-extended while the others in your sample don't.

char    int
c0 -> ffffffc0
80 -> ffffff80
61 -> 00000061
Here's a solution:
char ch = 0xC0;
printf("%x", ch & 0xff);

This will mask out the upper bits and keep only the lower 8 bits that you want.

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