请教关于输入输出的问题

#include <stdio.h>
#include <stdlib.h>
int main(void)
{
FILE * fp;
float a[2]={0,0};//如果你用%f的话就定义为float类型，如果用double类型的话，就要用%lf~~

fp=fopen("1.txt","r");

// fread(a,sizeof(double),2,fp);
for (int i=0;i<2;i++)
{
    fscanf(fp,"%f",&a[i]);
    printf("a is %f\n\n",a[i]);
}
fclose(fp);
fp = fopen("2.txt","w");
for (i=0;i<2;i++)
{
    fprintf(fp,"%f",a[i]);
    fprintf(fp," ");
}
fclose(fp);

return 0;
}