Hi all

New to c programming , please feel to modofy my code below...this is what i want to do,
1. i want to read a file and update this file once the user has input the number..
2. i want to show the contents of the file with the user input entered..

required output..

1,2,3,4,5,6,7,8,9,10 - u have entered no. 3

below 2 code snippets can read a file and accept input from user but i can not list the whole file contents...

Code:
#include <stdio.h>
#define MAX 20
char string[20];

int main()
{
    FILE *f;
    int x;


    f=fopen("file.txt","r");
    if (!f)
{   printf("Couldn't open file....try again !! txt\n");
        return 1;
}
    while(fgets(string, 20, f))
{
    printf("%s", string);
}

        fclose(f);
        return 0;
}
above code lists the whole contents of the file....(a.out), how can i modify it so that i can prompt the user to input the number and then print the whole file...can this be done...how...thanks in advance....indy