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2010-05-25T14:21:17Z

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2010-05-25T10:30:12Z

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==Global class variable==

<source lang="cpp">#include<iostream.h>
class test
{
int i;
public:
test()
{
i=25;
for(int ctr=0; ctr<10;ctr++)
{
cout<<"Counting at"<<ctr<<"\n";
}
}
~test(){};
};
test anObject;
main()
{
return 0;
}</source>
<pre class=codeResult>Counting at0
Counting at1
Counting at2
Counting at3
Counting at4
Counting at5
Counting at6
Counting at7
Counting at8
Counting at9</pre>

==Global variables are known throughout the entire program and may be used by any piece of code.==

<source lang="cpp">#include <stdio.h>

void func1(void), func2(void);

int count;

main(void)
{
count = 100;
func1();
return 0;
}

void func1(void)
{
int temp;

temp = count;
func2();
printf("count is %d", count); /* will print 100 */
}

void func2(void)
{
int count;

for(count=1; count<10; count++)
putchar(".");
}</source>

==Use a global variable==

<source lang="cpp">#include <iostream>
using namespace std;
void func1();
void func2();
int count; // This is a global variable.
int main()
{
int i; // This is a local variable
for(i=0; i<10; i++) {
::count = i * 2;
func1();
}
return 0;
}
void func1()
{
cout << "count: " << ::count; // access global count
cout << "\n";
func2();
}
void func2()
{
int count;
for(count=0; count<3; count++)
cout << ".";
}</source>
<pre class=codeResult>count: 0
...count: 2
...count: 4
...count: 6
...count: 8
...count: 10
...count: 12
...count: 14
...count: 16
...count: 18
...</pre>

==Use :: to reference global variable==

<source lang="cpp">#include <iostream>
using namespace std;
int global_name = 1001;
int main(void){
int global_name = 1; // Local variable
cout << "Local variable value " << global_name << "\n";
cout << "Global variable value " << ::global_name << "\n";
}</source>

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C++ Tutorial/Language Basics/global variable - История изменений

в 14:21, 25 мая 2010

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