why my commented (//....) code is not working?

Question

#include<iostream>
using namespace std;
int main(){
// int sum=0;
// cout<<"Enter number"<<endl;
// cin>>k;
// for(int i=0; 1<i<=9;i++){
// if(i%2==0){
// sum=sum+i;
// }
// else{
// return 0;
// }
//
//cout<<sum;
// }
//}

int sum=0, k;
cout<<"enter number";
cin>>k;
for(int i = 0; i <= k; i++)
if(i % 2 == 0)
sum += i;
cout << sum << endl;
}

Answer 1

Why do you repeat every question you made?
https://www.sololearn.com/discuss/2736984/?ref=app
https://www.sololearn.com/discuss/2736979/?ref=app
https://www.sololearn.com/discuss/2736978/?ref=app
https://www.sololearn.com/discuss/2736981/?ref=app
https://www.sololearn.com/discuss/2736980/?ref=app
https://www.sololearn.com/discuss/2736983/?ref=app
https://www.sololearn.com/discuss/2736982/?ref=app

Answer 2

♨ Soumik 🎶 Yes maybe but if she can add more details like what she is doing here so we can tell.

Answer 3

Because when you consider a line of code as a comment, compiler ignores that line while running.

Answer 4

Adeeba

Comments are used for understanding purpose means anyone can understand easily what is going on in the code. Compiler ignore comments to execute.

Answer 5

🅘🅜 🅰🅹 !!! Zahra ツ

The question meant to say why the code will not work if the comments were to be removed.

Answer 6

First Problem:
int sum=0;
...
cin>>k;
=> there ist no k. sum ist the only variable you declared.

Second Problem:
for(int i=0; 1<i<=9;i++)

Here is an explanation what happens in this code:
"1 < i <= 9" translates to
(1< i) <= 9, which results in either
0 <= 9 or 1 <= 9 (depending on i)
And this expression is always true. You basically create an infinite loop.

And here is a description of how to achieve what you want:
To express "a < b < c" you need to split it up into "a<b" and "b<c". Combine these with a logical 'and' operator (a < b && b<c).