Precedence & associativityerror: reference to overloaded function couldcout<<a ==b<<endl;not be resolved: did vou mean to call it?3.4+2/5*0.6ok.theresultis3.4.warning: self-comparison always evaluates toif (a&b!=b)//dosomethingfalseelse//dosomethingelse
Precedence & associativity cout << a == b << endl; 3.4 + 2 / 5 * 0.6 error: reference to overloaded function could not be resolved; did you mean to call it? ok. the result is 3.4. if (a & b != b) // do something else // do something else warning: self-comparison always evaluates to false
Precedence & associativityvector<int>v[1, 2,4, 8, 16]vector<int>::const_iteratorit = v.begin();while (it != vend()(cout<<*it<<endl;利用优先级写出更简洁的code++it;while (it!= vend() cout << *it++ << endl;
Precedence & associativity vector<int> v{1, 2, 4, 8, 16}; vector<int>::const_iterator it = v.begin( ); while (it != v.end( )) { cout << *it << endl; ++it; } 利用优先级写出更简洁的code while (it != v.end( )) cout << *it++ << endl;
Increment & decrement注意区分表达式的执行结果/效果和表达式的值。An expression is composed of one or more operands and yields a result when itis evaluated.++ainta=3,b=3;变量a自增1，表达式的值为自增后的值cout<<++a<<endlcout << a <<endla++cout<<b++<<endl;变量a自增1，表达式的值为自增前的值cout<<b<<endl;
Increment & decrement 注意区分表达式的执行结果/效果和表达式的值。 An expression is composed of one or more operands and yields a result when it is evaluated. int a = 3, b = 3; cout << ++a << endl; cout << a << endl; cout << b++ << endl; cout << b << endl; ++a 变量a自增1，表达式的值为自增后的值 a++ 变量a自增1，表达式的值为自增前的值
Order of evaluationPrecedence specifies how the operands are grouped.It says nothing about the order in which the operands are evaluated.In most cases, the order is largely unspecified.inta=Expr1+Expr2*Expr3;It is an error for an expression to refer to and change the same objectinta=++i+i++*i;// warning: multiple unsequenced modifications to
Order of evaluation int a = Expr1 + Expr2 * Expr3; Precedence specifies how the operands are grouped. It says nothing about the order in which the operands are evaluated. In most cases, the order is largely unspecified. It is an error for an expression to refer to and change the same object. int a = ++i + i++ * i; // warning: multiple unsequenced modifications to 'i