Elementary cellular automaton: Difference between revisions

=={{header|C++}}==

<lang cpp>#include <bitset>

#include <stdio.h>

#define SIZE 80

#define RULE 30

#define RULE_TEST(x) (RULE & 1 << (7 & (x)))

void evolve(std::bitset<SIZE> &s) {

int i;

std::bitset<SIZE> t(0);

t[SIZE-1] = RULE_TEST( s[0] << 2 | s[SIZE-1] << 1 | s[SIZE-2] );

t[ 0] = RULE_TEST( s[1] << 2 | s[ 0] << 1 | s[SIZE-1] );

for (i = 1; i < SIZE-1; i++)

t[i] = RULE_TEST( s[i+1] << 2 | s[i] << 1 | s[i-1] );

for (i = 0; i < SIZE; i++) s[i] = t[i];

}

void show(std::bitset<SIZE> s) {

int i;

for (i = SIZE; --i; ) printf("%c", s[i] ? '#' : ' ');

printf("\n");

}

int main() {

int i;

std::bitset<SIZE> state(1);

state <<= SIZE / 2;

for (i=0; i<10; i++) {

show(state);

evolve(state);

}

return 0;

}</lang>

{{out}}

<pre> # |

### |

## # |

## #### |

## # # |

## #### ### |

## # # # |

## #### ###### |

## # ### # |

## #### ## # ### |</pre>