confusion!

Question

hi,i am a new programmer....i am begining to learn c++ and i made a my first calculator(kinda):

#include <iostream>

int main(){
int a,b,result;
std::cout<<"enter first number:";
std::cin>>a;
std::cout<<"\n";
std::cout<<"enter second number:";
std::cin>>b;
std::cout<<"\n";
result=a*b;
std::cout<<"the result is:"<<result;

return 0;}

and it works too...but the confusion is when i used "std::cout<<endl:" instead of "std::cout"\n" it didnt work, why is that?
thank you for your support!

Answer 1

Not slower but it is bad practice. If you do "using namespace std;" at the beginning of your program, you can't ever have a variable callend endl or cout or lots of others - because all of std gets dumped into your namespace. Since std is so big, nameclashes like that are a real problem!
If you are going to use it, do it inside functions. For example

int main(){
using namespace std;
cout << ...
}

That way You don't have to write "std::" in your main function, but you don't run into problems everywhere else. The way you did it is totally fine!

Answer 2

it's std::cout << std::endl;

Answer 3

oh, thank you very much.

Answer 4

Just write
using namespace std;
at the beginning of the program so you dont have to write std:: every time you use a function of the standard library.
Your method is fine too

Just a suggestion

Answer 5

yea, I know that but someone told me if you use that at the beginning ,your program runs slower than it should be...Is it true? ,if somebody knows please tell me..

Answer 6

oh..and one more thing, for example this is a program..

#include <iostream>
using namespace std;

int main()
{
cout << "Hello world!" << endl;
cout << "I love programming!";
return 0;
}
now...how do you write the same exact program without using 'using namespace std;'

Answer 7

Just put std:: in front of cout and endl like you did in your original post.