в 14:21, 25 мая 2010

2010-05-25T14:21:17Z

Admin: 1 версия: Импорт контента...

2010-05-25T10:30:17Z

1 версия: Импорт контента...

Новая страница

==A Help system that process multiple requests.==

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

int main() {
char choice;

for(;;) {
do {
cout << "Help on:\n";
cout << " 1. if\n";
cout << " 2. switch\n";
cout << " 3. for\n";
cout << " 4. while\n";
cout << " 5. do-while\n";
cout << " 6. break\n";
cout << " 7. continue\n";
cout << " 8. goto\n";
cout << "Choose one (q to quit): ";
cin >> choice;
} while( choice < "1" || choice > "8" && choice != "q");

if(choice == "q") break;

cout << "\n\n";

switch(choice) {
case "1":
cout << "The if:\n\n";
break;
case "2":
cout << "The switch:\n\n";
break;
case "3":
cout << "The for:\n\n";
break;
case "4":
cout << "The while:\n\n";
break;
case "5":
cout << "The do-while:\n\n";
break;
case "6":
cout << "The break:\n\n";
break;
case "7":
cout << "The continue:\n\n";
break;
case "8":
cout << "The goto:\n\n";
break;
}
cout << "\n";
}

return 0;
}</source>
<pre class=codeResult>Help on:
1. if
2. switch
3. for
4. while
5. do-while
6. break
7. continue
8. goto
Choose one (q to quit): 4

The while:

Help on:
1. if
2. switch
3. for
4. while
5. do-while
6. break
7. continue
8. goto
Choose one (q to quit): 2

The switch:

Help on:
1. if
2. switch
3. for
4. while
5. do-while
6. break
7. continue
8. goto
Choose one (q to quit): q</pre>

==A switch without break statements.==

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

int main()
{
int i;

for(i=0; i<5; i++) {
switch(i) {
case 0: cout << "less than 1\n";
case 1: cout << "less than 2\n";
case 2: cout << "less than 3\n";
case 3: cout << "less than 4\n";
case 4: cout << "less than 5\n";
}
cout << "\n";
}

return 0;
}</source>
<pre class=codeResult>less than 1
less than 2
less than 3
less than 4
less than 5
less than 2
less than 3
less than 4
less than 5
less than 3
less than 4
less than 5
less than 4
less than 5
less than 5</pre>

==Calculator based on switch statement==

<source lang="cpp">#include <iostream>
int result;
char oper_char;
int value;
int main()
{
result = 0;
while (true) {
std::cout << "Result: " << result << "\n";
std::cout << "Enter operator and number: ";

std::cin >> oper_char >> value;

if ((oper_char == "q") || (oper_char == "Q"))
break;

switch (oper_char) {
case "+":
result += value;
break;
case "-":
result -= value;
break;
case "*":
result *= value;
break;
case "/":
if (value == 0) {
std::cout << "Error:Divide by zero\n";
std::cout << " operation ignored\n";
} else
result /= value;
break;
default:
std::cout << "Unknown operator " << oper_char << "\n";
break;
}
}
return (0);
}</source>

==char navigation based on switch==

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

int main() {
char choice;

cout << "Help on:\n";
cout << " 1. if\n";
cout << " 2. switch\n";
cout << "Choose one: ";
cin >> choice;

cout << "\n";

switch(choice) {
case "1":
cout << "The if:\n\n";
break;
case "2":
cout << "The switch:\n\n";
break;
default:
cout << "Selection not found.\n";
}

return 0;
}</source>
<pre class=codeResult>Help on:
1. if
2. switch
Choose one: 1
The if:</pre>

==switch case falling through==

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

int main()
{
int i;

for(i=0; i<5; i++) {
switch(i) {
case 1:
case 2:
case 3:
cout << "i is less than 4";
break;
case 4:
cout << "i is 4";
break;
}
cout << "\n";
}

return 0;
}</source>
<pre class=codeResult>i is less than 4
i is less than 4
i is less than 4
i is 4</pre>

==switch statement based on data type==

<source lang="cpp">#include <iostream.h>
void increase (void* data, int type)
{
switch (type)
{
case sizeof(char) : (*((char*)data))++; break;
case sizeof(short): (*((short*)data))++; break;
case sizeof(long) : (*((long*)data))++; break;
}
}
int main ()
{
char a = 5;
short b = 9;
long c = 12;
increase (&a,sizeof(a));
increase (&b,sizeof(b));
increase (&c,sizeof(c));
cout << (int) a << ", " << b << ", " << c;
return 0;
}</source>
<pre class=codeResult>6, 10, 13"</pre>

==The switch==

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

int main()
{
int num;

cout << "Enter a number from 1 to 3: ";
cin >> num;

switch(num) {
case 1:
cout << "111.\n";
break;
case 2:
cout << "222.\n";
break;
case 3:
cout << "333.\n";
break;
default:
cout << "You must enter either 1, 2, or 3.\n";
}

return 0;
}</source>
<pre class=codeResult>Enter a number from 1 to 3: 2
222.</pre>

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

C++ Tutorial/Operators statements/switch - История изменений

в 14:21, 25 мая 2010

Admin: 1 версия: Импорт контента...