shifting elements in an array of strings and fill with zeros

Question

I want to shift elements in my array to right and fill the shifted elements with zero (as string) . but it\'s a bit more difficult than i thought.

this program reads a t

Answer 1

#include 
#include 
#define SIZE_MAX 20

int main()
{

    FILE *fPTR;

    char num_first[SIZE_MAX]; // string input
    char num_second[SIZE_MAX];
    char num_zeros[SIZE_MAX];//array for leading zeros
    int i = 0;
    char numbers[SIZE_MAX];

    if ((fPTR = fopen("input.txt", "r")) == NULL) // our file contains two line of integers. one at each
    {
        puts("File could not be opened.");
    }
    else
    {
        if (fgets(num_first, SIZE_MAX, fPTR) != NULL) // reads first line and saves to num_first
            puts(num_first); // prints first number
        if (fgets(num_second, SIZE_MAX, fPTR) != NULL) // reads second line and saves to num_second
            puts(num_second); // prints second number
        fclose(fPTR);
    }
    for ( i = 0; i < SIZE_MAX; i++)
    {
        num_zeros[i] = '0';//fill array with '0's
    }
    // getting strings lengths
    int fLEN = strlen(num_first);
    if ( fLEN && num_first[fLEN - 1] == '\n')
    {
        num_first[fLEN - 1] = '\0';//remove trailing newline
        fLEN--;
    }
    int sLEN = strlen(num_second);
    if ( sLEN && num_second[sLEN - 1] == '\n')
    {
        num_second[sLEN - 1] = '\0';//remove trailing newline
        sLEN--;
    }
    int e = 0; // difference between two string lengths
    // here we get the difference and it's the place which i want to shif the arrays
    if (fLEN>sLEN) // first string is bigger than second
    {
        e = fLEN-sLEN;
        num_zeros[e] = '\0';//terminate array leaving e leading zeros
        strcat ( num_zeros, num_second);
        strcpy ( num_second, num_zeros);
    }
    else if (sLEN>fLEN) // second string is bigger than first
    {
        e = sLEN-fLEN;
        while ( fLEN >= 0)//start at end of array
        {
            num_first[fLEN + e] = num_first[fLEN];//copy each element e items from current location
            fLEN--;// decrement length
        }
        while ( e)// number of leading zeros
        {
            e--;
            num_first[e] = '0';// set first e elements to '0'
        }
    }
    else // there is no difference between two strings
    {
        //e = fLEN-sLEN;
    }
    puts(num_first);
    puts(num_second);
    return 0;
}