Program of calculating sum n even natural number | In C

Practice Program

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Program of calculating sum of n even natural numbers

Solution : through for loop

void main()
{
    int n,i,sum = 0;;
    printf("Sum of how many numbers: ");
    scanf("%d",&n);
    
    //at every iteration we are assigning 
    //(current_value + (i *2)) to new value of sum. 
    for(i=0; i<n; i++)
    {
        sum = sum+(i*2);
    }
    
    
    printf("Sum of  %d even natural numbers are %d",n,sum);
   

}

Output1

Sum of how many numbers:5

Sum of 5 even natural numbers are 20.

Output2

Sum of how many numbers:10

Sum of 15 even natural numbers are 90.

Output3

Sum of how many numbers:15

Sum of 15 even natural numbers are 210.

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Solution : through while loop

void main()
{
    int n,i,sum = 0;;
    printf("Sum of how many numbers: ");
    scanf("%d",&n);
      i=1;
    //at every iteration we are assigning
    //(current_value + i ) to new value of sum.
    while(i<=n)
    {
        sum = sum+(i*2);
        i++;
    }


    printf("Sum of first %d natural numbers are %d",n,sum);


}

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Solution: from do-while loop

void main()
{
    int n,i,sum = 0;;
    printf("Sum of how many numbers: ");
    scanf("%d",&n);
      i=1;
    //at every iteration we are assigning
    //(current_value + i ) to new value of sum.
    do
    {
        sum = sum+(i*2);
        i++;
    }while(i<=n)


    printf("Sum of first %d natural numbers are %d",n,sum);


}

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defining a function 'sum_of_even' which will return sum of n numbers.

int sum_of_even(int n)
{
    int i,sum=0;

     //at every iteration we are assigning
    //(current_value + i ) to new value of sum.
    for(i=1;i<=n;i++)
    {
        sum = sum+i;
    }
    return sum;
}

Using above define function 'sum_of_even':

void main()
{
    int n,result;
    printf("How many  numbers of sum you want: ");
    scanf("%d",&n);


   result  = sum_of_even(5);


   printf("Sum of first %d numbers are %d",n,result);



}

Output1

Sum of how many numbers:5

Sum of 5 even natural numbers are 20.

Using above define function 'sum_of_even':

void main()
{
    int n,result;
    printf("How many  numbers of sum you want: ");
    scanf("%d",&n);


   result  = sum_of_even(10);


   printf("Sum of first %d numbers are %d",n,result);



}

Output2

Sum of how many numbers:10

Sum of 10 even natural numbers are 90.

Using above define function 'sum_of_even':

void main()
{
    int n,result;
    printf("How many  numbers of sum you want: ");
    scanf("%d",&n);


   result  = sum_of_even(15);


   printf("Sum of %d even natural numbers  are %d",n,result);



}

Output3

Sum of how many numbers:15

Sum of 15 even natural numbers are 210.

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