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...
); int f2(std::string) noexcept; // 函数作用域中的声明 std::cout << "f2(\"bad\"):" << f2("bad") << '\n'; std::cout << "f2(\"42\"):" << f2("42") << '\n'; } // 简单的非成员函数,返回 int int f1() { return 007; } // 拥有异常说明和函数 try 块的函数 ...
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
#include <iostream>#include <string>voiddouble_string(std::string&s){s+=s;// 's' is the same object as main()'s 'str'}intmain(){std::stringstr="Test";double_string(str);std::cout<<str<<'\n';} When a function's return type is lvalue reference, the function call expression ...
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>...
#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 <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<<'...
{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; ...
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...
resume(); }); // 潜在的未定义行为:访问潜在被销毁的 *this // std::cout << "新线程 ID:" << p_out->get_id() << '\n'; std::cout << "新线程 ID:" << out.get_id() << '\n'; // 这样没问题 } void await_resume() {} }; return awaitable{&out}; } struct task { ...