Bucles anidados de C ++

Un bucle se puede anidar dentro de otro bucle. C ++ permite al menos 256 niveles de anidamiento.

Sintaxis

La sintaxis de un nested for loop declaración en C ++ es la siguiente:

for ( init; condition; increment ) {
   for ( init; condition; increment ) {
      statement(s);
   }
   statement(s); // you can put more statements.
}

La sintaxis de un nested while loop declaración en C ++ es la siguiente:

while(condition) {
   while(condition) {
      statement(s);
   }
   statement(s); // you can put more statements.
}

La sintaxis de un nested do...while loop declaración en C ++ es la siguiente:

do {
   statement(s); // you can put more statements.
   do {
      statement(s);
   } while( condition );

} while( condition );

Ejemplo

El siguiente programa usa un bucle for anidado para encontrar los números primos del 2 al 100:

#include <iostream>
using namespace std;
 
int main () {
   int i, j;
   
   for(i = 2; i<100; i++) {
      for(j = 2; j <= (i/j); j++)
         if(!(i%j)) break; // if factor found, not prime
         if(j > (i/j)) cout << i << " is prime\n";
   }
   
   return 0;
}

Esto produciría el siguiente resultado:

2 is prime
3 is prime
5 is prime
7 is prime
11 is prime
13 is prime
17 is prime
19 is prime
23 is prime
29 is prime
31 is prime
37 is prime
41 is prime
43 is prime
47 is prime
53 is prime
59 is prime
61 is prime
67 is prime
71 is prime
73 is prime
79 is prime
83 is prime
89 is prime
97 is prime