C Exercises: Explain whether a number is Keith or not
C Numbers: Exercise-37 with Solution
Write a program in C to check if a number is Keith or not(with explanation).
Test Data
Input a number : 1537
Sample Solution:
C Code:
# include <stdio.h>
# include <stdlib.h>
# include <stdbool.h>
# include <math.h>
int lenCount(int nm)
{ int ctr=0;
while(nm>0)
{
nm=nm/10;
ctr++;
}
return ctr;
}
int main()
{
int num1=0,arr1[10],num2=0,flg=0,i=0,sum=0,kk;
printf("\n\n Check whether a number is Keith or not: \n");
printf(" Sample Keith numbers: 197, 742, 1104, 1537, 2208, 2580, 3684, 4788, 7385..\n");
printf(" -----------------------------------------------------------------------\n");
printf(" Input a number : ");
scanf("%d",&num1);
num2=num1;
for(i=lenCount(num2)-1;i>=0;i--)
{
arr1[i]=num1 % 10;
num1/=10;
}
while(flg==0)
{
for(i=0;i<lenCount(num2);i++)
sum+=arr1[i];
if(sum==num2)
{
flg=1;
kk=1;
}
if(sum>num2)
{
flg=1;
kk=0;
}
for(i=0;i<lenCount(num2);i++)
{
printf(" %d",arr1[i]);
if(i!=lenCount(num2)-1)
{
arr1[i]=arr1[i+1];
printf(" + ");
}
else
{
arr1[i]=sum;
printf(" = %d",arr1[i]);
}
}
printf("\n");
sum=0;
}
if(kk==1)
{
printf(" The given number is a Keith Number.\n");
}
if(kk==0)
{
printf(" The given number is not a Keith Number.\n");
}
}
Sample Output:
Input a number : 1537 1 + 5 + 3 + 7 = 16 5 + 3 + 7 + 16 = 31 3 + 7 + 16 + 31 = 57 7 + 16 + 31 + 57 = 111 16 + 31 + 57 + 111 = 215 31 + 57 + 111 + 215 = 414 57 + 111 + 215 + 414 = 797 111 + 215 + 414 + 797 = 1537 The given number is a Keith Number.
Pictorial Presentation:
Flowchart:

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C Programming: Tips of the Day
Why do C and C++ compilers allow array lengths in function signatures when they're never enforced?
It is a quirk of the syntax for passing arrays to functions.
Actually it is not possible to pass an array in C. If you write syntax that looks like it should pass the array, what actually happens is that a pointer to the first element of the array is passed instead.
Since the pointer does not include any length information, the contents of your [] in the function formal parameter list are actually ignored.
Ref : https://bit.ly/3fhlvdH
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