how do i add all the elements of the for loop? - c

Question

#include <stdio.h>
int even_numbers_sum(){
int d;
for(d=0;d<=100;d++){
if(d%2==0){
printf("\n this is even number loop %d",d);
}
}
int sum;
sum=sum+d;
printf("\n the value of total sum of the loop %d",sum);
return sum;
}
int main(){
even_numbers_sum();
}
my main aim is to calculate the sum of all the elemets of for loop i took a for loop and described its value and put a equation (if) to pass anynumber if its only even other wise it will not work and i have to add all those even number till 100 how do i do it

Answer 1

Initialised sum to 0 at the beginning. Changed the return type of the function to void as int was unnecessary. Sum has to be incremented in the if statement.
#include <stdio.h>
void even_numbers_sum(){
int d;
int sum=0;
for(d=0;d<=100;d++){
if(d%2==0){
printf("\n this is even number loop %d",d);
sum=sum+d;
}
}
printf("\n the value of total sum of the loop %d",sum);
}
int main(){
even_numbers_sum();
}

Answer 2

look the following code. I've written this code for any number if you want to change the upper bound instead of 100 , you just have to pass the integer to the function i.e. if you want to get the sum of all even integers from 0 to 100, you have to pass 100 while calling the function.
#include <stdio.h>
void even_numbers_sum(int i){
int d;
int sum=0;
for(d=0;d<=i;d+=2){
printf("\n this is even number loop %d",d);
sum=sum+d;
}
}
printf("\n the value of total sum of the loop %d",sum);
}
int main(){
even_numbers_sum(100);
return 0;
}
1.first change is here in function declaration and definition you have to write int i in the parentheses.
void even_numbers_sum(int i)
2.Secondly there is no need to put the condition if you want to start from 0. it can be done by simply increment d by 2.
for(d=0;d<=i;d+=2)
3.Your main method has return type int so there should be some integer returned.
return 0;
I hope this will help you to solve your problem. If there is anything which you want to ask I'll be glad to help you.

Answer 3

Firstly, you should initialize sum as 0 at begin. sum may be not 0 without initialization.
Secondly, in your code, sum will be only add with the final even number (100), not add each each even number from 0 to 100.
A correct example as below:
#include <stdio.h>
int even_numbers_sum()
{
int d, sum = 0; // initialize sum as 0
for (d = 0; d <= 100; d++) {
if (d % 2 == 0) {
printf("\n this is even number loop %d", d);
sum = sum + d; // add each even number to sum
}
}
// sum=sum+d; // This line code will add final even number and sum
printf("\n the value of total sum of the loop %d", sum);
return sum;
}
int main()
{
even_numbers_sum();
}