cquery没有匹配的功能来调用'to_upper'

如何解决cquery没有匹配的功能来调用'to_upper'

#include <iostream>
#include <string>
#include <boost/algorithm/string.hpp>
using namespace std;

int main() {
  string city1,city2;
  cout << ("Please enter your citys name");
  cin >> city1;
  cout << ("Please enter your citys second name");
  cin >> city2;
  cout << city1 [0,1,2,3,4];
  cout << city2 [0,4];
  boost::to_upper(city1,city2);
  cout << city1,city2;
}

这是我的代码，出于某种原因boost :: to_upper（city1，city2）;收到错误：[cquery]调用“ to_upper”没有匹配的功能

解决方法

boost::algorithm::to_upper被声明为（来自boost reference）

template<typename WritableRangeT> 
void to_upper(WritableRangeT & Input,const std::locale & Loc = std::locale());

，因此您只能将一个字符串传递给此函数。更换

boost::to_upper(city1,city2);

使用

boost::to_upper(city1);
boost::to_upper(city2);

使代码编译，示例输出为Please enter your citys namePlease enter your citys second nameosLONDON。 它缺少换行符，还有一个错误-对逗号运算符的误解。通常，逗号用于分隔参数或数组元素，但以行分隔

cout << city1 [0,1,2,3,4];
cout << city2 [0,4];
// ...
cout << city1,city2;

使用逗号运算符。逗号运算符采用两个操作数，其值是右操作数的值（例如int x = (1,2);变量x等于2之后）。上面的代码等同于

cout << city1[4];
cout << city2[4];
// ...
cout << city1;
city2;

最后，正确的代码是

#include <iostream>
#include <string>
#include <boost/algorithm/string.hpp>
using namespace std;

int main() {
  string city1,city2;
  cout << "Please enter your citys name" << std::endl;
  cin >> city1;
  cout << "Please enter your citys second name" << std::endl;
  cin >> city2;
  cout << city1 << std::endl;
  cout << city2  << std::endl;
  boost::to_upper(city1);
  boost::to_upper(city2);
  cout << city1 << std::endl << city2 << std::endl;
}