Home > Backend Development > C++ > Should I Use a Signed or Unsigned Index Variable When Iterating Over a std::vector?

Should I Use a Signed or Unsigned Index Variable When Iterating Over a std::vector?

Patricia Arquette
Release: 2024-11-11 22:46:03
Original
302 people have browsed it

Should I Use a Signed or Unsigned Index Variable When Iterating Over a std::vector?

Iteration over std::vector: Signed vs Unsigned Index Variable

When iterating over a vector in C , you can use either a signed or unsigned index variable. However, there are some subtle differences to be aware of.

Using an unsigned index variable is generally preferred because it eliminates the possibility of a negative index, which would result in undefined behavior. For example, this code works fine:

for (unsigned i = 0; i < polygon.size(); i++) {
    sum += polygon[i];
}
Copy after login

However, this code would generate a warning:

for (int i = 0; i < polygon.size(); i++) {
    sum += polygon[i];
}
Copy after login

The warning occurs because the comparison i < polygon.size() is between a signed and an unsigned integer expression. This can lead to unexpected behavior in some cases.

Therefore, it is best to always use an unsigned index variable when iterating over a vector.

You may also prefer to use iterators instead of indices. Iterators provide a more abstract way of accessing the elements of a vector, and they can help to prevent you from making mistakes. For example, you could use the following code to iterate over a vector:

for (std::vector<int>::iterator it = polygon.begin(); it != polygon.end(); ++it) {
    sum += *it;
}
Copy after login

In general, it is considered good practice to use iterators rather than indices when iterating over a vector.

The above is the detailed content of Should I Use a Signed or Unsigned Index Variable When Iterating Over a std::vector?. For more information, please follow other related articles on the PHP Chinese website!

source:php.cn
Statement of this Website
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn
Latest Articles by Author
Popular Tutorials
More>
Latest Downloads
More>
Web Effects
Website Source Code
Website Materials
Front End Template