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cin << name << endl; cout >> "my name is " << name << endl;

collin sim
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    `if (ans == "Yes" || ans == "yes") return getchoice2();` -- Look at your code carefully -- you are returning an `int` (the choice) from a function that returns a `double`. In addition, you are recursively calling `getmusclemass()` instead of using the proper looping constructs. Your `getmusclemass()` function should not be doing any input or output -- its job should be to accept values as parameters, and returns a value based on calculations, not I/O. As a matter of fact, maybe you should learn what function parameters are, since your program lacks any use of them. – PaulMcKenzie Aug 15 '17 at 20:52

1 Answers1

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Problem

When you say cin >> smth, you want to get precisely smth, nothing more. End-line marker is not part of it, so it's not consumed. Unless you would have a special type for line, but there is no such thing in standard library.

When you use getline you say you want to get a line. A line is string that ends with \n, the ending is integral part of it.

So the problem is that std::cin leaves an end-line \n character in buffer.

Example

std::cin >> smth;

+---+---+---+---+---+----+
|'H'|'e'|'l'|'l'|'o'|'\n'|      // In smth will be "Hello"
+---+---+---+---+---+----+

+----+
|'\n'|                          // But new-line character stays in buffer
+----+

std::cin >> smth2;              // Its same like you would press just an 'enter', so smth2 is empty

Solution

  • Use std::cin.getline

or

  • Use std::cin >> smth; + std::cin.ignore();
kocica
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  • No, all the standard `operator>>` will skip whitespace before reading into a variable. That will consume the `'\n'` left in the buffer. It is only if you mix `>>` and `getline` that you might get an empty line. – Bo Persson Aug 15 '17 at 21:56