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/*
** ifactor.c -- print prime factorization of a number
**
** Ray Gardner -- 1985 -- public domain
*/
#include <stdio.h>
#include <stdlib.h>
int prevfact = 0;
void factor (long);
void show (long, int);
void main (int argc, char *argv[])
{
while ( --argc )
factor(atol(*++argv));
}
void factor (long n)
{
long d;
int k;
long n0 = n;
prevfact = 0;
printf("%ld ",n);
if ( n < 2 )
{
printf("is less than 2.\n");
return;
}
else if ( n > 2 )
{
d = 2;
for ( k = 0; n % d == 0; k++ )
n /= d;
if ( k )
show(d,k);
for ( d = 3; d * d <= n; d += 2 )
{
for ( k = 0; n % d == 0; k++ )
n /= d;
if ( k )
show(d,k);
}
}
if ( n > 1 )
{
if ( n == n0 )
printf(" is prime");
else show(n,1);
}
printf("\n");
}
void show (long d, int k)
{
if ( prevfact )
printf(" * ");
else printf(" = ");
prevfact++;
printf("%ld",d);
if ( k > 1 )
printf("^%d",k);
}
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