std::ostringstream oss;             // 默認(rèn)空緩沖
oss << "Value=" << 42 << ", Pi=" 
    << std::fixed << std::setprecision(3) << 3.14159;
// 獲取結(jié)果
std::string s = oss.str();          // s == "Value=42, Pi=3.142"

std::string line = "123  45.6 OK";
// 將 line 內(nèi)容作為流緩沖
std::istringstream iss(line);

int    a;
double b;
std::string status;

// 按空白自動切分并轉(zhuǎn)換
if (iss >> a >> b >> status) {
    // a==123, b==45.6, status=="OK"
}

// 檢查是否完全消費(fèi)或錯誤
if (iss.fail() && !iss.eof()) {
    // 轉(zhuǎn)換中發(fā)生格式錯誤
}

std::stringstream ss;
ss << "X=" << 10 << ";Y=" << 20;
// 重設(shè)讀寫位置到開頭
ss.seekg(0);

// 逐字符讀取、跳過標(biāo)識
char    ch;
int     x, y;
ss >> ch >> ch >> x;   // 假設(shè)格式 "X=10"
ss >> ch >> ch >> y;   // 跳過 ";Y="

iss.exceptions(std::ios::failbit | std::ios::badbit);
try {
  int v; 
  iss >> v;  // 解析失敗即拋異常
} catch (const std::ios_base::failure& e) {
  // 處理錯誤
}

#include <iostream>
#include <sstream>
#include <iomanip>

int main() {
    // 構(gòu)建字符串
    std::ostringstream oss;
    oss << "Point(" 
        << std::setw(2) << std::setfill('0')
        << 7 << "," 
        << std::fixed << std::setprecision(1)
        << 3.14 << ")";
    std::string desc = oss.str();  // "Point(07,3.1)"
    std::cout << desc << "\n";

    // 解析回?cái)?shù)值
    std::istringstream iss(desc);
    char ch;
    int ix;
    double dy;
    if ( (iss >> ch >> ch >> ix >> ch >> dy >> ch).good() ) {
        std::cout << "Parsed: x=" << ix << ", y=" << dy << "\n";
    } else {
        std::cerr << "Parse error\n";
    }

    // 讀寫混合：累加偏移
    std::stringstream ss("100 200 300");
    int sum = 0, v;
    while (ss >> v) sum += v;  // sum=600
    std::cout << "Sum=" << sum << "\n";

    return 0;
}