C + + Learning

#include <iostream>int  main () {    std::cout<<'test \ n' ;     int SJK;    Std::cin>>sjk;    Std::cout<<sjk;     return 0 ;}

#include <iostream>/using Std::cout; // using Std::endl; using namespace std; int Main () {    cout<<"test \ n";    cout<<Endl;             return 0 ;}

Namespace conflict issues

#include <iostream>//using namespace std;namespacea{intA=1;}namespaceb{intA=2;}intMain () {//int a=3;    using namespaceA; using namespaceb; Std::cout<<a<<"|"<<a::a<<"|"<<b::a<<Std::endl; return 0;}

function application

#include <iostream>using namespacestd;intSumintAintb) {    returnA +b;}intMain () {intA, B; CIN>>A; CIN>>b; cout<<"a+b="<<sum (A, b); return 0;}

Declaration and definition of a function

#include <iostream>using namespacestd;//function Declaration//int sum (int a, int b);intSumint,int);//parameter names can be omittedintMain () {intA, B; CIN>>A; CIN>>b; cout<<"a+b="<<sum (A, b); return 0;}//function DefinitionintSumintAintb) {    returnA +b;}

#include <iostream>using namespacestd;voida ();voidb ();voidA () {cout<<"a \ n"; b ();}voidB () {cout<<"b \ n"; A ();}intMain () {a (); return 0;}

Variable Range

#include <iostream>usingnamespace  std; int x, y; // Global variables are valid for any function void Change () {    x=+;} int Main () {change    ();    cout<<x;         return 0 ;}

C + + Learning