“setprecision”不是“std”的成员

Question

错误：

~> g++ ssstring.cpp
ssstring.cpp: In function ‘int main()’:
ssstring.cpp:12:31: error: ‘setprecision’ is not a member of ‘std’
ssstring.cpp:12:52: error: ‘numeric_limits’ is not a member of ‘std’
ssstring.cpp:12:74: error: expected primary-expression before ‘float’
ssstring.cpp:13:30: error: ‘setprecision’ is not a member of ‘std’
ssstring.cpp:13:51: error: ‘numeric_limits’ is not a member of ‘std’
ssstring.cpp:13:73: error: expected primary-expression before ‘float’
ssstring.cpp:14:28: error: ‘setprecision’ is not a member of ‘std’
ssstring.cpp:14:49: error: ‘numeric_limits’ is not a member of ‘std’
ssstring.cpp:14:71: error: expected primary-expression before ‘float’
anisha@linux-trra:~>

代码：

#include <sstream>
#include <iostream>
#include <string.h>

int main ()
{
    // Convert `lat`, `lons`, and `vehicleId` to string.
    float selectedPointLat = 2.2;
    float selectedPointLng = 2.3;
    float vehicleId        = 1.0;

    std :: stringstream floatToStringLat, floatToStringLng, floatToStringVehicleId;

    floatToStringLat       << std :: setprecision (std :: numeric_limits<float> :: digits10 + 1); floatToStringLat  << selectedPointLat;
    floatToStringLng       << std :: setprecision (std :: numeric_limits<float> :: digits10 + 1); floatToStringLng << selectedPointLng;
    floatToStringVehicleId << std :: setprecision (std :: numeric_limits<float> :: digits10 + 1); floatToStringVehicleId << vehicleId;

}

Answer 1

您需要为std::setprecision 包含标题<iomanip>，为std::numeric_limits 包含<limits>。这些引用告诉您要包​​含哪个标头。