【C代码练习20】输出前num个素数

#include<stdio.h>

int isprime(int x, int knownprimes[], int number_of_knownprimes);

int main(void)
{
const int number = 10;
int prime[number] = {2};
/*
int i;
for(i=0; i<number; i++)
{
printf("%d", prime[i]);

if( (i+1)%5 == 0 )
{
printf("\n");
}
else
{
printf("\t");
}
}
*/
int cnt = 1;
int i = 3;

{
int i;
printf("\t\t");
for(i=0; i<number; i++)
{
printf("%d\t", i);
}
printf("\n");
}

while(cnt < number)
{
if(isprime(i, prime, cnt))
{
prime[cnt++] = i;
}

{
printf("i=%d\tcnt=%d\t", i, cnt);
int i;
for(i=0; i<number; i++)
{
printf("%d\t", prime[i]);
}
printf("\n");
}

i++;
}

for(i=0; i<number; i++)
{
printf("%d", prime[i]);

if( (i+1)%5==0 )
{
printf("\n");
}
else
{
printf("\t");
}
}

return 0;
}

int isprime(int x, int knownprimes[], int number_of_knownprimes)
{
int ret = 1;
int i;

for(i=0; i<number_of_knownprimes; i++)
{
if(x%knownprimes[i] == 0)
{
ret = 0;
break;
}
}

return ret;
}