break; cout << x << endl; x++; } break语句只能跳出本层循环,假如你要跳出一个三重嵌套的循环,你就要使用包含其它的逻辑或者用一个goto语句跳出这个嵌套循环. case 在switch里面用来检测匹配 . default,switch catch catch 语句通常通过throw语句捕获一个异常. 这一页... class class-name : inheritance-li...
全局对象 std::cout 和std::wcout 控制实现定义类型(派生于 std::streambuf)流缓冲区的输出,它与标准 C 输出流 stdout 关联。 保证这些对象在首次构造 std::ios_base::Init 类型对象期间或之前初始化,并可以在拥有有序初始化的静态对象的构造函数和析构函数中使用(只要在定义对象前包含 <iostream>)。
语句 是依序执行的 C++ 程序片段。任何函数体都是语句的序列。例如: intmain(){intn=1;// 声明语句n=n+1;// 表达式语句std::cout<<"n = "<<n<<'\n';// 表达式语句return0;// 返回语句} C++ 包含下列类型的语句: 带标号语句
代码& 运行结果 #include<coroutine>#include<iostream>#include<stdexcept>#include<thread>autoswitch_to_new_thread(std::jthread&out){structawaitable{std::jthread*p_out;boolawait_ready(){returnfalse;}voidawait_suspend(std::coroutine_handle<>h){std::jthread&out=*p_out;if(out.joinable())throwstd:...
#include <iostream>structFoo{intn;Foo(){std::cout<<"static constructor\n";}~Foo(){std::cout<<"static destructor\n";}};Foo f;// static objectintmain(){std::cout<<"main function\n";} Output: static constructor main function static destructor ...
#include <bit> #include <bitset> #include <cstdint> #include <iostream> static_assert(std::popcount(0xFULL) == 4); int main() { for (const std::uint8_t x : {0, 0b00011101, 0b11111111}) std::cout << "popcount( " << std::bitset<8>(x) << " ) = " << std::popcount...
std::cout << std::setw(34) << #__VA_ARGS__ \ << " == " << __VA_ARGS__ << '\n' int main() { std::cout << std::boolalpha << std::left; SHOW(is_range<std::vector<double>>); SHOW(is_range<std::map<int, double>>); SHOW(is_range<double>); SHOW(is_range<A>...
{enum{CHAR, INT, DOUBLE} tag;union{charc;intn;doubled; }; };voidprint_s(constS&s) {switch(s.tag) {caseS::CHAR: std::cout << s.c <<'\n';break;caseS::INT: std::cout << s.n <<'\n';break;caseS::DOUBLE: std::cout << s.d <<'\n';break; ...
#include <vector>intmain(){// Create a vector containing integersstd::vector<int>v={8,4,5,9};// Add two more integers to vectorv.push_back(6);v.push_back(9);// Overwrite element at position 2v[2]=-1;// Print out the vectorfor(intn:v)std::cout<<n<<' ';std::cout<<'...
a function call or an overloaded operator expression of lvalue reference return type, such as std::getline(std::cin, str), std::cout << 1, str1 = str2, or ++it; (运算符重载并且返回值是引用的方法) a = b, a += b, a %= b, and all other built-in assignment and compound assig...