ARM Sitara Device is not detecting

#include <stdio.h>
#include<stdlib.h>
#include<string.h>
//#include<poll.h>
/*
 * hello.c
 */
int main(void) {
	printf("Hello World!\n");
	FILE *fp;
	int i = 0;
		fp = fopen("/sys/class/gpio/export","w");
		if(fp == NULL)
		{
				printf("err_no");
				return 0;
		}
		else
		{		fwrite("0",sizeof(char),1,fp);
				printf("in else");
				fclose(fp);
		}
		fp = fopen("/sys/class/gpio0/direction","w");
		if(fp == NULL)
				{
						printf("err_no_1");
						return 0;
				}
		else
				{		fwrite("out",sizeof(char),3,fp);
				printf("in else_1");
						fclose(fp);
				}

		while(1)
		{
		fp = fopen("/sys/class/gpio0/value","w");
		if(fp == NULL)
						{
								printf("err_no_1");
								return 0;
						}

				if(i < 100000)
						{		fwrite("1",sizeof(char),1,fp);
								fclose(fp);
						}
				if(i > 100000)
				{		fwrite("0",sizeof(char),1,fp);
						printf("in else_2");
							fclose(fp);
				}
				if(i > 200000)
					i = 0;

				i++;
		}
}