C++/Language/While
Содержание
- 1 Make the condition of the while loop always true
- 2 Nesting While Loops
- 3 Update of the value of num was done within the body of the loop
- 4 Use the break keyword to provide the user with the option of quitting the data entry
- 5 While loop Demo
- 6 While loop: outputs the numbers between 1 and 10
- 7 While loop: two conditions
- 8 While statement
Make the condition of the while loop always true
#include <iostream>
using namespace std;
int main(void)
{
int num;
char choice;
bool quit = false;
while (true)
{
cout << "Enter a positive number: ";
cin >> num;
if (num > 0)
break;
else
{
cout << "Number must be positive; try again (Y/N): ";
cin >> choice;
if (choice != "Y")
{
quit = true;
break;
}
}
}
if (quit == false)
cout << "The number you entered is " << num << " ";
else
cout << "You did not enter a positive number";
return 0;
}
Nesting While Loops
#include <iostream>
using namespace std;
int main(void)
{
int x = 0;
while (x++ < 5)
{
int y = 0;
while (y++ < 5)
cout << "X";
cout << "\n";
}
return 0;
}
Update of the value of num was done within the body of the loop
#include <iostream>
using namespace std;
int main(void)
{
int num = 0;
while (num++ < 10)
cout << num << " ";
return 0;
}
Use the break keyword to provide the user with the option of quitting the data entry
#include <iostream>
using namespace std;
int main(void)
{
int num;
char choice;
cout << "Enter a positive number: ";
cin >> num;
while (num <= 0)
{
cout << "Number must be positive; try again (Y/N): ";
cin >> choice;
if (choice == "Y")
{
cout << "Enter number: ";
cin >> num;
}
else
break;
}
cout << "The number you entered is " << num << " ";
return 0;
}
While loop Demo
#include <iostream>
using namespace std;
int main(void)
{
int num;
cout << "Enter a positive number: ";
cin >> num;
while (num <= 0)
{
cout << "Positive number: ";
cin >> num;
}
cout << "The number you entered is " << num << " ";
return 0;
}
While loop: outputs the numbers between 1 and 10
#include <iostream>
using namespace std;
int main(void)
{
int num = 1;
while (num <= 10)
{
cout << num << " ";
num++;
}
return 0;
}
While loop: two conditions
#include <iostream>
using namespace std;
int main(void)
{
int num;
char choice;
bool quit = false;
cout << "Enter a positive number: ";
cin >> num;
while (num <= 0 && quit == false)
{
cout << "Number must be positive; try again (Y/N): ";
cin >> choice;
if (choice != "Y")
{
cout << "Enter number: ";
cin >> num;
}
else
quit = true;
}
if (quit == false)
cout << "The number you entered is " << num << " ";
else
cout << "You did not enter a positive number";
return 0;
}
While statement
#include <iostream>
using namespace std;
int main()
{
int x, count = 0;
float sum = 0.0;
cout << "Please enter some integers: " << endl;
while( cin >> x ){
sum += x;
++count;
}
cout << "The average of the numbers: " << sum / count << endl;
return 0;
}