c++ - setprecision 不显示数字

Question

我有以下功能片段:

bool A_AbstractTester_Actor::Equals( int lineNumber, T_String valueText, double value, T_String expectedText, double expected, double accuracy )
{
    ...
    v_FailedText << std::setprecision(8) << "\nLine " << lineNumber  
     << ": EQUALS_DOUBLE FAILED, Value '" << valueText << "' (" << value 
     << "), Expected '" << expectedText << "' (" << expected << ")\n";

稍后我打印 v_FailedText，结果是:

Line 242: EQUALS_DOUBLE_FAILED, Value 'step' (0), Expected '1.0' (1)

我期望的是:

Line 242: EQUALS_DOUBLE_FAILED, Value 'step' (0.00000000), Expected '1.0' (1.00000000)

Answer 1

你应该使用 std::fixed操纵器。

bool A_AbstractTester_Actor::Equals( int lineNumber, T_String valueText, double value, T_String expectedText, double expected, double accuracy )
{
    ...
    v_FailedText << std::fixed << std::setprecision(8) "\nLine " << lineNumber  
     << ": EQUALS_DOUBLE FAILED, Value '" << valueText << "' (" << value 
     << "), Expected '" << expectedText << "' (" << expected << ")\n";