в 14:21, 25 мая 2010

2010-05-25T14:21:17Z

Admin: 1 версия: Импорт контента...

2010-05-25T10:31:04Z

1 версия: Импорт контента...

Новая страница

==an array of pointers to strings==

<source lang="cpp">#include <iostream>
using namespace std;
const int DAYS = 7;

int main(){
char* arrptrs[DAYS] = { "Sunday", "Monday", "Tuesday",
"Wednesday", "Thursday",
"Friday", "Saturday" };

for(int j=0; j<DAYS; j++)
cout << arrptrs[j] << endl;
return 0;
}</source>

==array accessed with array notation==

<source lang="cpp">#include <iostream>
using namespace std;

int main(){
int intarray[5] = { 31, 54, 77, 52, 93 };

for(int j=0; j<5; j++)
cout << intarray[j] << endl;
return 0;
}</source>

==array accessed with pointer==

<source lang="cpp">#include <iostream>
using namespace std;

int main(){
int intarray[] = { 31, 54, 77, 52, 93 };
int* ptrint;
ptrint = intarray;

for(int j=0; j<5; j++)
cout << *(ptrint++) << endl;
return 0;
}</source>

==array accessed with pointer notation==

<source lang="cpp">#include <iostream>
using namespace std;

int main(){
int intarray[5] = { 31, 54, 77, 52, 93 };

for(int j=0; j<5; j++)
cout << *(intarray+j) << endl;
return 0;
}</source>

==Array pointer==

<source lang="cpp">#include <iostream>
using namespace std;

int main()
{
int *i, j[10];
double *f, g[10];
int x;

i = j;
f = g;

for(x=0; x<10; x++)
cout << i+x << " " << f+x << "\n";

return 0;
}</source>
<pre class=codeResult>0x22ff30 0x22fed0
0x22ff34 0x22fed8
0x22ff38 0x22fee0
0x22ff3c 0x22fee8
0x22ff40 0x22fef0
0x22ff44 0x22fef8
0x22ff48 0x22ff00
0x22ff4c 0x22ff08
0x22ff50 0x22ff10
0x22ff54 0x22ff18</pre>

==Index a pointer as if it were an array==

<source lang="cpp">#include <iostream>
#include <cctype>
using namespace std;

int main()
{
char *p;
int i;
char str[80] = "This Is A Test";

cout << "Original string: " << str << "\n";

p = str;

for(i = 0; p[i]; i++) {
if(isupper(p[i]))
p[i] = tolower(p[i]);
else if(islower(p[i]))
p[i] = toupper(p[i]);
}

cout << "Inverted-case string: " << str;

return 0;
}</source>
<pre class=codeResult>Original string: This Is A Test
Inverted-case string: tHIS iS a tEST</pre>

==Output array address by using array pointer==

<source lang="cpp">#include <assert.h>
#include <iostream>
#include <iomanip>
char array[10] = "012345678";
int main()
{
for (int i = 0; i < 10; ++i) {
std::cout << std::hex;
std::cout << "&array[i]=0x" << reinterpret_cast<int>(&array[i]) <<
" (array+i)=0x" << reinterpret_cast<int>(array+i) <<
" array[i]=0x" << static_cast<int>(array[i]) << "\n",
std::cout << std::dec;
}
return (0);
}</source>
<pre class=codeResult>&array[i]=0x43d000 (array+i)=0x43d000 array[i]=0x30
&array[i]=0x43d001 (array+i)=0x43d001 array[i]=0x31
&array[i]=0x43d002 (array+i)=0x43d002 array[i]=0x32
&array[i]=0x43d003 (array+i)=0x43d003 array[i]=0x33
&array[i]=0x43d004 (array+i)=0x43d004 array[i]=0x34
&array[i]=0x43d005 (array+i)=0x43d005 array[i]=0x35
&array[i]=0x43d006 (array+i)=0x43d006 array[i]=0x36
&array[i]=0x43d007 (array+i)=0x43d007 array[i]=0x37
&array[i]=0x43d008 (array+i)=0x43d008 array[i]=0x38
&array[i]=0x43d009 (array+i)=0x43d009 array[i]=0x0</pre>

==passing array as a constant pointer==

<source lang="cpp">#include <iostream>
using namespace std;
void increase(int* const array, const int NUM_ELEMENTS);
void display(const int* const array, const int NUM_ELEMENTS);
int main()
{
const int NUM_SCORES = 3;
int highScores[NUM_SCORES] = {5, 3, 2};
cout << "passing array as a constant pointer.\n\n";
increase(highScores, NUM_SCORES);
cout << "passing array as a constant pointer to a constant.\n";
display(highScores, NUM_SCORES);
return 0;
}
void increase(int* const array, const int NUM_ELEMENTS)
{
for (int i = 0; i < NUM_ELEMENTS; ++i)
array[i] += 500;
}
void display(const int* const array, const int NUM_ELEMENTS)
{
for (int i = 0; i < NUM_ELEMENTS; ++i)
cout << array[i] << endl;
}</source>

==Relationship between pointers and arrays==

<source lang="cpp">#include <iostream>
using namespace std;
void increase(int* const array, const int NUM_ELEMENTS);
void display(const int* const array, const int NUM_ELEMENTS);
int main()
{
const int NUM_SCORES = 3;
int highScores[NUM_SCORES] = {5, 3, 2};
cout << "using array name as a constant pointer.\n";
cout << *highScores << endl;
cout << *(highScores + 1) << endl;
cout << *(highScores + 2) << "\n\n";
cout << "passing array as a constant pointer.\n\n";
increase(highScores, NUM_SCORES);
cout << "passing array as a constant pointer to a constant.\n";
display(highScores, NUM_SCORES);
return 0;
}
void increase(int* const array, const int NUM_ELEMENTS)
{
for (int i = 0; i < NUM_ELEMENTS; ++i)
array[i] += 500;
}
void display(const int* const array, const int NUM_ELEMENTS)
{
for (int i = 0; i < NUM_ELEMENTS; ++i)
cout << array[i] << endl;
}</source>

==Use a 2-D array of pointers to create a dictionary==

<source lang="cpp">#include <iostream>
#include <cstring>
using namespace std;

int main() {

char *dictionary[][2] = {
"A", "AA",
"B", "BB",
"C", "CC",
"D", "DD",
"E", "EE",
"", ""
};
char word[80];
int i;

cout << "Enter word: ";
cin >> word;

for(i = 0; *dictionary[i][0]; i++) {
if(!strcmp(dictionary[i][0], word)) {
cout << dictionary[i][1] << "\n";
break;
}
}

if(!*dictionary[i][0])
cout << word << " not found.\n";

return 0;
}</source>
<pre class=codeResult>Enter word: word
word not found.</pre>

← Предыдущая	Версия 14:21, 25 мая 2010
(нет различий)

C++ Tutorial/Array/array pointer - История изменений

в 14:21, 25 мая 2010

Admin: 1 версия: Импорт контента...