/*
* 质因数分解，求一个数的质因数，例如90 = 2*3*3*5
*/
bool isPrime(int number)
{
double dnum = (double)number;
int stopNum = sqrt(dnum);
for(int i = 2; i <= stopNum; i++)
{ if(0 == number % i)
return false;
}
return true;
}
void PrimeFactor(int number)
{
int factor = 2;
if(number == factor && isPrime(factor))
{
printf("%d\n", factor);
return;
}
while(number != factor)
{
while(number % factor == 0 && isPrime(factor))
{
printf("%d ", factor);
number /= factor;
}
factor ++;
if(number == factor && isPrime(factor))
printf("%d\n", factor);
} //while
}
int main()
{
printf("input a number:\n");
int number;
scanf("%d", &number); //例如：90
printf("factor(s) of %d is(are) : ", number);
PrimeFactor(number); //例如：90 = 2*3*3*5
system("pause");
return 0;
}