C++ Tutorial/Operators statements/break

Материал из C\C++ эксперт
Перейти к: навигация, поиск

Break a for loop

#include <iostream> 
using namespace std; 
 
int main() 
{ 
  int t; 
 
  // Loops from 0 to 9, not to 100! 
  for(t=0; t<100; t++) { 
    if(t==10) break; 
    cout << t << " "; 
  } 
 
  return 0; 
}
0 1 2 3 4 5 6 7 8 9

Break an infinite loop

#include <iostream> 
using namespace std; 
 
int main() 
{ 
  int t, count;  
 
  for(t=0; t<10; t++) { 
    count = 1; 
    for(;;) { 
      cout << count << " "; 
      count++; 
      if(count==10) break; 
    }  
    cout << "\n"; 
  } 
 
  return 0; 
}
1 2 3 4 5 6 7 8 9
1 2 3 4 5 6 7 8 9
1 2 3 4 5 6 7 8 9
1 2 3 4 5 6 7 8 9
1 2 3 4 5 6 7 8 9
1 2 3 4 5 6 7 8 9
1 2 3 4 5 6 7 8 9
1 2 3 4 5 6 7 8 9
1 2 3 4 5 6 7 8 9
1 2 3 4 5 6 7 8 9

Break from while

#include<iostream.h>
int main()
{
  int x,y,s;
  cin >> x >> y;
  s=0;
  while(1)
  {
    if(s==0)break;
    s +=x;
  }
  cout<<s<<endl;
}
1
2
2

Demonstrating a Forever Loop

#include <iostream>
int menu();
void DoTaskOne();
void DoTaskMany(int);
using namespace std;
int main()
{
   bool exit = false;
   for (;;)
   {
      int choice = menu();
      switch(choice)
      {
        case (1):
            DoTaskOne();
            break;
        case (2):
            DoTaskMany(2);
            break;
        case (3):
            DoTaskMany(3);
            break;
        case (4):
            continue;  
            break;
        case (5):
            exit=true;
            break;
        default:
            cout << "Please select again! " << endl;
            break;
      }             
      if (exit == true)
         break;
   }                
   return 0;
}                   
int menu()
{
   int choice;
   cout << " **** Menu **** "   << endl << endl;
   cout << "(1) Choice one. "   << endl;
   cout << "(2) Choice two. "   << endl;
   cout << "(3) Choice three. " << endl;
   cout << "(4) Redisplay menu. " << endl;
   cout << "(5) Quit. "    << endl << endl;
   cout << ": ";
   cin >> choice;
   return choice;
}
void DoTaskOne()
{
   cout << "Task One! " << endl;
}
void DoTaskMany(int which)
{
   if (which == 2)
      cout << "Task Two! " << endl;
   else
      cout << "Task Three! " << endl;
}