c++ - 无法编译 bool 连接

Question

我的 Catch 测试框架中有以下简单表达式。理想情况下，如果测试失败，测试应该发出警告。

不幸的是，Catch 无法编译以下代码片段:

#define CATCH_CONFIG_MAIN
#include "catch2.hpp"

TEST_CASE("Simple") {
    int a = 4;
    int b = 1;
    CHECK(a == 5 || b == 2);
}

Visual Studio 2015 发出以下错误:

error C2676: Binary operator "||": "const Catch::BinaryExpr<LhsT,const int &>" does not define this operator or a conversion for this operator of to suitable type

我希望是这样的:

4==5 || 1==2 => false || false => false

这对 Catch 是否可行，还是我必须使用额外的括号:

#define CATCH_CONFIG_MAIN
#include "catch2.hpp"

TEST_CASE("Simple") {
    int a = 4;
    int b = 1;
    CHECK((a == 5 || b == 2));
}

Answer 1

如果您阅读 docs你会发现一个部分说:

CHECK( a == 2 || b == 1 ); This expression is too complex because of the || operator. If you want to check that one of several properties hold, you can put the expression into parenthesis (unlike with &&, expression decomposition into several CHECKs is not possible).

还要注意...

I would expect something like the following:

4==5 || 1==2 => false || false => false

...您的期望略有偏差。 || 是短路的，这意味着如果第一个操作数的计算结果为 false，则不会计算第二个操作数。