Anonymous user
Pascal's triangle: Difference between revisions
m
+D
(Added Haskell example) |
m (+D) |
||
Line 47:
end Pascals_Triangle;
</ada>
=={{header|D}}==
There is similarity between Pascal's triangle and [[Sierpinski triangle]]. Their difference are the initial line and the operation that act on the line element to produce next line. The following is a generic pascal's triangle implementation for positive number of lines output (n).
<d>import std.stdio, std.string, std.format : fmx = format ;
string Pascal(alias dg, T, T initValue)(int n) {
string output ;
void append(T[] l) {
output ~= repeat(" ", (n - l.length + 1)*2) ;
foreach(e; l) output ~= fmx("%4s", fmx("%4s",e)) ;
output ~= "\n" ;
}
if(n > 0) {
T[][] lines = [[initValue]] ;
append(lines[0]) ;
for(int i = 1 ; i < n ; i++) {
lines ~= lines[i-1] ~ initValue ; // length + 1
for(int j = 1 ; j < lines[i-1].length ; j++)
lines[i][j] = dg(lines[i-1][j], lines[i-1][j-1]) ;
append(lines[i]) ;
}
}
return output ;
}
string delegate(int n) GenericPascal(alias dg, T, T initValue)(){
mixin Pascal!(dg, T, initValue) ;
return &Pascal ;
}
char xor(char a, char b) { return a == b ? '_' : '*' ; }
void main() {
auto pascal = GenericPascal!((int a, int b) { return a + b; }, int , 1 ) ;
auto sierpinski = GenericPascal!(xor, char, '*') ;
foreach(i ; [1,5,9]) writef(pascal(i)) ;
// an order 4 sierpinski triangle is a 2^4 lines generic pascal triangle with xor operation
foreach(i ; [16]) writef(sierpinski(i)) ;
}</d>
=={{header|Haskell}}==
| |||