#include <stdio.h>
#include <stdlib.h>

int main()
{
    int ch;
    FILE *input= fopen("C:\\Users\\toby\\Desktop\\2012\\input.txt","r");
    FILE *above50= fopen("‪‪C:\\Users\\toby\\Desktop\\2012\\above50.txt","w");
    FILE *below20= fopen("C:\\Users\\toby\\Desktop\\2012\\below20.txt","w");
    while(fscanf(input,"%d",&ch)!=EOF)
    {
            if (ch>50)
......................