c++ Programs Internet 1

8/8/2019 c++ Programs Internet 1

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1. Language Basics

1.1 Introduction( 4 ) 1. 9. namespace( 14 )

1. 2. main function( 2 ) 1. 10. global namespace( 2 )

1. 3. Variables( 6 ) 1. 11. comments( 1 )

1. 4. Variable size( 1 ) 1.12. static( 3 )

1. 5. global variable( 2 ) 1. 13. using( 2 )

1. 6. block scope variable( 7 ) 1. 14. mutable( 2 )1. 7. Expression( 1 ) 1. 15. extern( 1 )

1. 8. const( 3 )

--------------------------------------------------------------

1. 1. Introduction

1. 1. 1. This is a simple C++ program

1. 1. 2. Calculating with integer constants

1. 1. 3. Working with integer variables

1. 1. 4. Using the assignment operator--------------------------------------------------------------

1. 1. 1. This is a simple C++ program#include

using namespace std;

int main()

{

cout


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1. 3. Variables

1. 3. 1.Assign value to a variable

1. 3. 2. Dynamic initialization.

1. 3. 3.A scoping example

1. 3. 4. Using the unary scope resolution operator

1. 3. 5. Finding maximum and minimum values for data types1. 3. 6. Comparing data values

---------------------------------------------

1. 3. 1. Assign value to a variable

#include


int main()

{

int length; // this declares a variablelength = 7; // this assigns 7 to length

cout


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1. 3. 5. Finding maximum and minimum values for data types

#include

#include

using std::cout;

using std::endl;

using std::numeric_limits;

int main() {cout


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void func2()

{

int count;

for(count=0; count


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output:

inner i: 50

outer i: 10

-------------------------------

1. 6. 4. Names in inner scopes can hide names in outer scopes.

#include

#include

int main()

{

for (int i = 0; i < 10; ++i)

{

int x = 2;if (x < i)

{double x = 3.4;

std::cout


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int n::counter::n = 7;

int main()

{

int counter = 0;

int n = 10;

std::cout


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int main()

{

int a[] = { 10, 20, 30 };

f( a );

cout


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output:

10 9 8 7 6 5 4 3 2 1 0

20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0100 99 98 97 96 95 94 93 92 91 90

----------------------------

1. 9. 3. A nested namespace

#include


namespace MyNamespace1 {int i;

namespace MyNamespace2 { // a nested namespace

int j;

}

}

int main(){MyNamespace1::i = 19;

MyNamespace1::MyNamespace2::j = 10; // this is right

cout


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namespace second

{

double var = 3.1416;

}

int main () {{

using namespace first;

cout


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namespace Example

{

const double PI = 3.14159;

void printValues();

namespace Inner{

enum Years { FISCAL1 = 1990, FISCAL2, a };

}

}

namespace

{

double doubleInUnnamed = 88.22;}

int main()

{

Example::printValues();

return 0;

}

void Example::printValues()

{cout


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("input error in readAndProcessSum()");

}

// return sum

return sum;

}

}

a

I/O exception: input error in readAndProcessSum()

---------------------------------

1. 9. 12. Using unnamed namespaces.

#include

#include

namespace {

int i = 10;}

namespace {

int j; // same unnamed namespace

namespace X {

int i = 20;

}

namespace Y = X;

int f() { return i; }}

int main(){

std::cout


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60

2

2

5

-----------------------------------1. 10. global namespace

1. 10. 1. Use explicit std:: qualification

1. 10. 2. Bring only a few names into the global

namespace

--------------------------------------

1. 10. 1. Use explicit std:: qualification

#include

int main()

{

int val;

std::cout > val;

std::cout


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}

1 2 3 4 5 67 8 9 10 11 12 13

14 15 16 17 18 19 20

21 22 23 24 25 26

27 28 29 30

--------------------------------------

1. 12. 2. Use static variable to compute a running average of

numbers entered by the user

#include


int f(int i);

int main(){int num;

do {

cout > num;

if(num != -1)

cout


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const int count = sizeof boxes/sizeof boxes[0];

cout


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return 0;

}

1900"

---------------------

1. 14. 2. Demonstrating storage-class specifier mutable

#include

using std::cout;

using std::endl;

class MyClass {public:

MyClass( int v )

{

value = v;

}

int getValue() const{

return value++;

}

private:

mutable int value;

};

int main()

{const MyClass test( 99 );

cout

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