当我编译traingl e_test. cpp程序时，当gtest. h头文件包含在该文件中时，我得到以下错误。

In file included from c:\mingw\lib\gcc\mingw32\6.3.0\include\gtest\gtest-message.h:55:0,
                 from c:\mingw\lib\gcc\mingw32\6.3.0\include\gtest\gtest-assertion-result.h:46,
                 from c:\mingw\lib\gcc\mingw32\6.3.0\include\gtest\gtest.h:59,
                 from traingle_test.cpp:2:
c:\mingw\lib\gcc\mingw32\6.3.0\include\gtest\internal\gtest-port.h:1238:8: error: 'mutex' in namespace 'std' does not name a type
   std::mutex mu_;
        ^~~~~
c:\mingw\lib\gcc\mingw32\6.3.0\include\gtest\internal\gtest-port.h:1239:8: error: 'condition_variable' in namespace 'std' does not name a type
   std::condition_variable cv_;
        ^~~~~~~~~~~~~~~~~~
c:\mingw\lib\gcc\mingw32\6.3.0\include\gtest\internal\gtest-port.h: In member function 'void testing::internal::Notification::Notify()':
c:\mingw\lib\gcc\mingw32\6.3.0\include\gtest\internal\gtest-port.h:1225:21: error: 'mutex' is not a member of 'std'
     std::lock_guard<std::mutex> lock(mu_);
                     ^~~
c:\mingw\lib\gcc\mingw32\6.3.0\include\gtest\internal\gtest-port.h:1225:21: error: 'mutex' is not a member of 'std'
c:\mingw\lib\gcc\mingw32\6.3.0\include\gtest\internal\gtest-port.h:1225:31: error: template argument 1 is invalid
     std::lock_guard<std::mutex> lock(mu_);

错误讯息

traingle_test.cpp

#include "traingle.h"
#include <gtest/gtest.h>
namespace {
TEST (TraingleTest, InvalidSides){
    EXPECT_EQ(-1, TypeOfTraingle(-10, 20, 30));
    EXPECT_EQ(-1, TypeOfTraingle(10, -20, 30));
    EXPECT_EQ(-1, TypeOfTraingle(3, 4, -8));
}
}

traingle.cpp

#include "traingle.h"
/* Return values
1 for equilateral, 2 for isosceles, 3 for scalan
0 for traingle can't be formed with given sides
-1 if any side value is invalid, say -ve
*/
int TypeOfTraingle(int a, int b, int c){
    if(a<0 || b<0 || c<0)
     return -1;
    if(!(a+b > c && b + c > a && a + c > b))
     return 0;
    else if (a==b && b==c)
     return 2;
    else
     return 3;
}

traingle.h

#ifndef __TRIANGLE_H
#define __TRIANGLE_H

int TypeOfTraingle(int, int, int);

#endif

我这里有3个文件traingle.cpp（计算在这里完成），traingle_test.cpp（测试用例编写）和traingle.h（包含函数声明）。测试用例文件需要与traingle.cpp链接，输出是多少测试用例通过，基于测试用例值（x，y，z）的三角形类型（等边、等腰和不等边三角形）将显示为下图所示