C Exercises: Find the happy numbers between 1 to 1000

Last update on May 27 2022 12:18:16 (UTC/GMT +8 hours)

C Numbers: Exercise-14 with Solution

Write a program in C to find the happy numbers between 1 to 1000.

Sample Solution:

C Code:

# include <stdio.h>
# include <math.h>
# include <stdlib.h>
# include <stdbool.h>


int SumOfSquNum(int givno)
{
    int SumOfSqr = 0;
    while (givno)
    {
        SumOfSqr += (givno % 10) * (givno % 10);
        givno /= 10;
    }
    return SumOfSqr;
}
bool checkHappy(int chkhn)
{
    int slno, fstno;
    slno = fstno = chkhn;
    do
    {
        slno = SumOfSquNum(slno);
        fstno = SumOfSquNum(SumOfSquNum(fstno));
    }
    while (slno != fstno);
    return (slno == 1);
}
int main()
{
int j,ctr;
	printf("\n\n Find the Happy numbers between 1 to 1000: \n");
	printf(" ----------------------------------------------\n");
	printf(" The happy numbers between 1 to 1000 are: ");

 for (j=1;j<=1000;j++)
		{
			if (checkHappy(j))
				printf("%d ",j);

		}
printf("\n");		
 }

Sample Output:

 The happy numbers between 1 to 1000 are: 1 7 10 13 19 23 28 31 32 44 49.....

Pictorial Presentation:

C programming: Find the happy numbers between 1 to 1000.

Flowchart:

C Programming Code Editor:

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C Programming: Tips of the Day

Static variable inside of a function in C

The scope of variable is where the variable name can be seen. Here, x is visible only inside function foo().

The lifetime of a variable is the period over which it exists. If x were defined without the keyword static, the lifetime would be from the entry into foo() to the return from foo(); so it would be re-initialized to 5 on every call.

The keyword static acts to extend the lifetime of a variable to the lifetime of the programme; e.g. initialization occurs once and once only and then the variable retains its value - whatever it has come to be - over all future calls to foo().

Ref : https://bit.ly/3fOq7XP