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ID:52395578
大小:453.06 KB
页数:73页
时间:2020-04-05
《计算机软件基础与c复习.ppt》由会员上传分享,免费在线阅读,更多相关内容在教育资源-天天文库。
1、计算机软件基础与C++复习1.Abetter“C”(1)引用必须初始化。intcount=0;int&refCount=count;initializerefCount=1;count+=count;int*ptrCount=&refCount;#definePAI3.1415926preprocessorconstdoublePAI=3.1415926;compiler在C++中常用const变量代替宏定义:constintYES=1;//这种定义有类型信息,更安全constTypeName=ConstExpression;—Declaresavariabletohaveacons
2、tantvalueconstintx=123;inty=x;y=x;constintz=y;CanbeusedinanyplacewhereweuseconstexpressionMustbeinitializedunlessyoumakeanexplicitexterndeclaration—externallinkageDon’tmodifythevaluedirectlyorindirectlyCanputinheaderfile—internallinkagevoidmain(){constintx;x=7;int*ptr=&x;inta;cin>>a;constintsiz
3、e=a;doubleclassAverage[size];}errorC2734:'x':constobjectmustbeinitializedifnotexternerrorC2166:l-valuespecifiesconstobjecterrorC2440:'initializing':cannotconvertfrom'constint*'to'int*‘ConversionlosesqualifierserrorC2057:expectedconstantexpressionerrorC2466:cannotallocateanarrayofconstantsize0er
4、rorC2133:'classAverage':unknownsize(2)常量修饰Const限定符C++允许初始化新分配的对象float*thingPtr=newfloat(3.14159);char*pChar=newchar(‘a’);C++可用new动态建立数组char*string=newchar[25];intsize;cin>>size;int*arrayInt=newint[size];C++用delete[]删除动态建立的数组delete[]string;delete[]arrayInt;(3)运算符new和delete运算符::是作用域分辨符,用它可以访问隐藏的全
5、局变量。#includedoublevalue=1.233;intmain(){intvalue=7;cout<<"Localvalue="<f(a,b)char*a;floatb;{printf(“a:%s,b:%f”,a,b);}main(){f(12.3,12.3);}C++#includef(char*a,f
6、loatb){cout<<“a:”<7、ybasketballPlaywithtoyPlaythestockmarket………intiabs(inti);longlabs(longl);doublefabs(doubled);intabs(inti);longabs(longl);doubleabs(doubled);abs(-10);abs(-1000000);doubleabs(3.14159);参数类型voidprint(inti);voidprint(char*s);参数个数intadd
7、ybasketballPlaywithtoyPlaythestockmarket………intiabs(inti);longlabs(longl);doublefabs(doubled);intabs(inti);longabs(longl);doubleabs(doubled);abs(-10);abs(-1000000);doubleabs(3.14159);参数类型voidprint(inti);voidprint(char*s);参数个数intadd
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