Csmartprogramming

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Definition of perfect number or What is perfect number? 

Perfect number is a positive number which sum of all positive divisors excluding that number is equal to that number. For example 6 is perfect number since divisor of 6 are 1, 2 and 3.  Sum of its divisor is

1 + 2+ 3 =6

Note: 6 is the smallest perfect number.

Next perfect number is 28 since 1+ 2 + 4 + 7 + 14 = 28

Some more perfect numbers: 496, 8128

Code 1:

1. C program to check perfect number

#include<stdio.h>

int main(){

  int n,i=1,sum=0;

  printf("Enter a number: ");

  scanf("%d",&n);

  while(i<n){

      if(n%i==0)

           sum=sum+i;

          i++;

  }

  if(sum==n)

      printf("%d is a perfect number",i);

  else

      printf("%d is not a perfect number",i);

  return 0;

}

Sample output:

Enter a number: 6

6 is a perfect number

Code 2:

1. C program to find perfect numbers

2. C perfect number code

3. Perfect number program in c language

#include<stdio.h>

int main(){

  int n,i,sum;

  int min,max;

  printf("Enter the minimum range: ");

  scanf("%d",&min);

  printf("Enter the maximum range: ");

  scanf("%d",&max);

  printf("Perfect numbers in given range is: ");

  for(n=min;n<=max;n++){

    i=1;

    sum = 0;

    while(i<n){

      if(n%i==0)

           sum=sum+i;

          i++;

    }

    if(sum==n)

      printf("%d ",n);

  }

  return 0;

}

Sample output:

Enter the minimum range: 1

Enter the maximum range: 20

Perfect numbers in given range is: 6

Code 3:

3. C program to print perfect numbers from 1 to 100

#include<stdio.h>

int main(){

  int n,i,sum;

 

  printf("Perfect numbers are: ");

  for(n=1;n<=100;n++){

    i=1;

    sum = 0;

    while(i<n){

      if(n%i==0)

           sum=sum+i;

          i++;

    }

    if(sum==n)

      printf("%d ",n);

  }

  return 0;

}

Output:

Perfect numbers are: 6 28

3. Wap to reverse a number in c

#include<stdio.h>

int main(){

    int num,r,reverse=0;

    printf("Enter any number: ");

    scanf("%d",&num);

    for(;num!=0;num=num/10){

         r=num%10;

         reverse=reverse*10+r;

    }

    printf("Reversed of number: %d",reverse);

    return 0;

}

Sample output:

Enter any number: 123

Reversed of number: 321

How to write power in c

#include<stdio.h>

int main(){

  int pow,num,i=1;

  long int sum=1;

  printf("\nEnter a number: ");

  scanf("%d",&num);

  printf("\nEnter power: ");

  scanf("%d",&pow);

  while(i<=pow){

            sum=sum*num;

            i++;

  }

  printf("\n%d to the power %d is: %ld",num,pow,sum);

  return 0;

}

Code for swapping in c

#include<stdio.h>

int main(){

    int a,b,temp;

   

    printf("Enter any two integers: ");

    scanf("%d%d",&a,&b);

    printf("Before swapping: a = %d, b=%d",a,b);

    temp = a;

    a = b;

    b = temp;

    printf("\nAfter swapping: a = %d, b=%d",a,b);

    return 0;

}

C program for swapping of two numbers using pointers

#include<stdio.h>

int main(){

    int a,b;

    int *ptra,*ptrb;

    int *temp;

    printf("Enter any two integers: ");

    scanf("%d%d",&a,&b);

    printf("Before swapping: a = %d, b=%d",a,b);

    ptra = &a;

    ptrb = &b;

     temp = ptra;

    *ptra = *ptrb;

    *ptrb = *temp;

    printf("\nAfter swapping: a = %d, b=%d",a,b);

    return 0;

}

Sample output:

Enter any two integers: 5 10

Before swapping: a = 5, b=10

After swapping: a = 10, b=10

Swapping program in c using function

#include<stdio.h>

void swap(int *,int *);

int main(){

    int a,b;

   

    printf("Enter any two integers: ");

    scanf("%d%d",&a,&b);

    printf("Before swapping: a = %d, b=%d",a,b);

    swap(&a,&b);

    printf("\nAfter swapping: a = %d, b=%d",a,b);

    return 0;

}

void swap(int *a,int *b){

    int *temp;

    temp = a;

    *a=*b;

    *b=*temp;

}

Sample output:

Enter any two integers: 3 6

Before swapping: a = 3, b=6

After swapping: a = 6, b=6