最近用C++写代码的时候,发现C++居然没有自己的字符串格式化的方法(PS:C++20才推出了自己format),所以如果不支持C++20,就没有现成的用,在网上找了一圈,发现了某位大神自己写的C++字符串格式化的工具,就是一个Format.h头文件,可以直接用,很方便

Github地址:https://github.com/arajar/format

Format.h具体代码如下

#pragma once#include <string>
#include <vector>
#include <stdlib.h>
#include <iostream>
#include <algorithm>
#include <sstream>
#include <iomanip>namespace util
{class ArgBase{public:ArgBase() {}virtual ~ArgBase() {}virtual void Format(std::ostringstream &ss, const std::string& fmt) = 0;};template <class T>class Arg : public ArgBase{public:Arg(T arg) : m_arg(arg) {}virtual ~Arg(){}virtual void Format(std::ostringstream &ss, const std::string& fmt){ss << m_arg;}private:T m_arg;};class ArgArray : public std::vector < ArgBase* >{public:ArgArray() {}~ArgArray(){std::for_each(begin(), end(), [](ArgBase* p){ delete p; });}};static void FormatItem(std::ostringstream& ss, const std::string& item, const ArgArray& args){int index = 0;int alignment = 0;std::string fmt;char* endptr = nullptr;index = strtol(&item[0], &endptr, 10);if (index < 0 || index >= args.size()){return;}if (*endptr == ','){alignment = strtol(endptr + 1, &endptr, 10);if (alignment > 0){ss << std::right << std::setw(alignment);}else if (alignment < 0){ss << std::left << std::setw(-alignment);}}if (*endptr == ':'){fmt = endptr + 1;}args[index]->Format(ss, fmt);return;}template <class T>static void Transfer(ArgArray& argArray, T t){argArray.push_back(new Arg<T>(t));}template <class T, typename... Args>static void Transfer(ArgArray& argArray, T t, Args&&... args){Transfer(argArray, t);Transfer(argArray, args...);}template <typename... Args>std::string Format(const std::string& format, Args&&... args){if (sizeof...(args) == 0){return format;}ArgArray argArray;Transfer(argArray, args...);size_t start = 0;size_t pos = 0;std::ostringstream ss;while (true){pos = format.find('{', start);if (pos == std::string::npos){ss << format.substr(start);break;}ss << format.substr(start, pos - start);if (format[pos + 1] == '{'){ss << '{';start = pos + 2;continue;}start = pos + 1;pos = format.find('}', start);if (pos == std::string::npos){ss << format.substr(start - 1);break;}FormatItem(ss, format.substr(start, pos - start), argArray);start = pos + 1;}return ss.str();}
}

使用方法

#include <iostream>
#include "Format.h"int main()
{std::string format_str = util::Format("There are {0} fools in the world",10);std::cout << format_str << std::endl;return 0;
}