• the_tech_beast@lemmy.mlOP
    link
    fedilink
    arrow-up
    0
    ·
    3 years ago
    #include <iostream>
    using namespace std;
    void sum()
    {
        int a, b, s;
        cin >> a >> b;
        s = a + b;
        cout << s;
    }
    int main()
    {
        sum();
    }
    

    Also why does this function return a value?

    for example, a = 45 and b = 45

    I get the sum as 90

            • tmpodA
              link
              fedilink
              arrow-up
              5
              ·
              3 years ago

              No. Printing something to the console (pushing something to cout with the << operator) is not the same as returning a value.

              Think of returns like what you have in math. When you have a function, let’s say

              int double(int n) {
                  return 2 * n;
              }
              

              that returns an int, calling it will “replace” the expression with its result, much like in math. So in this instance, doing 3 + double(2) would be like doing 3 + 4. Math is the same way; if you have a function, f(x) = 2x, doing 3 + f(2) would be the same as doing 3 + 4.

              Printing to the console involves doing I/O (input/output), and actually writing a string to a file, which then the terminal can display.

            • ChinaNumberOne@lemmy.ml
              link
              fedilink
              arrow-up
              4
              arrow-down
              1
              ·
              3 years ago

              don’t know if you are a beginner to programming in general or c/c++ specifically but it’s better to start with c before c++, it’s simpler and clearer (than c++) to a beginner

              then cout syntax is absolutely horrible and very misleading, use c’s printf or, if you can, use fmt, it’s super fast and even simpler than c’s printf

              • glibg10b@lemmy.ml
                link
                fedilink
                arrow-up
                1
                ·
                1 year ago

                If you want to learn C++, you should start with C++. Starting with C will form unsafe habits and teach unsafe paradigms that have been replaced by language features or parts of the C++ standard library

                it’s simpler and clearer (than c++) to a beginner

                A language only seems as clear as the tutorial used to teach it. If you think the basics of C++ can be better taught using a C tutorial,. you’ve been looking at the wrong C++ tutorials. Transitioning from C to C++ will be a confusing process for a beginner

            • LunaticHacker@lemmy.ml
              link
              fedilink
              arrow-up
              1
              ·
              3 years ago

              Of course they aren’t the same. try to achieve the same output with int sum() instead of void sum() this small exercise will help you understand the difference