nth_prime.c

#include<stdio.h>
#include<math.h>
int is_prime(int p){
	if(p<=1) return 0;
	int i=2;
	int sqrt_p=sqrt(p);
	while(i<=sqrt_p)
		if(p%i++==0)
			return 0;
	return 1;
}

/**
* USAGE: ./a.out 10001 
**/
int main(int argc, char *argv[]){
	if(argc<2) return 1;
	int total = atoi(argv[1]);
	int i=1;
	int count=0;
	while(count<total){
		if(is_prime(i)) count++;
		i++;
	}
	return i-1;
}