在串联COUT声明数组大小 [英] Concatenating an array size in cout statement

问题描述

我试图输出在我的数组元素的对象的数量，但是该语法是不一样的，因为它是用于Java

I'm trying to output the number of element-objects in my array, but the syntax for that is not the same as it is for Java:

    // print list of all messages to the console
void viewSent()
{
    cout << "You have " << sent.size() << " new messages.\n";//Error: left of '.size' must have class/struct,union
    std::cout << "Index      Subject" << '\n';

    for (size_t i = 0; i < sent.size(); ++i)
    {
        std::cout << i << "    : " << sent[i].getSubject() << '\n';
    }
}

如果.size不C ++语法的工作有哪些呢？

if the .size doesn't work in C++ syntax, what does?

推荐答案

Java数组的C ++相当于是的std ::矢量。 sent.size（）是让大小的正确方法。

The C++ equivalent of a Java array is std::vector. sent.size() is the correct way to get the size.

您不发表您的定义发送，但它应该是的std ::矢量＆lt;＆YourObject GT;发送; ，也许还指定初始大小和/或值

You didn't post your definition of sent but it should be std::vector<YourObject> sent;, perhaps with initial size and/or values also specified.

我猜你试图用C数组 - 不这样做，C风格的数组有奇怪的语法和行为历史原因和实在没有必要在C ++中曾经使用它们

I'm guessing you tried to use a C-style array -- don't do that, C-style arrays have strange syntax and behaviour for historical reasons and there is really no need to use them ever in C++.

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