arrays from txt in c (long numbers) - c

Question

400000000000;499999999999;VISA;
50000000;59999999;MASTERCARD;
67000000;67999999;MAESTRO;
fields: 1. Range Start 2. Range End, 3 Name.
[Start Range] and [End Range] fields can be from 1 to 16 characters (digits) in length.
The program's objective is as follows:
First Request to enter 16-digit card number.
Card number input, verification and processing use char [n] type (Simbol array)
Second:Check for an entry corresponding to the entered card number can be found in a text file if I enter 45000000000 it's between 400000000000 and 499999999999 so i need to put a text in a autput name VISA.
And i can't use long long types... as i undrstand i need to use arrays...
Third Request to enter the amount in the format "nnnn.mm", where nnnn-1 to 4 digits long amount of lats, but mm - 2-digit amount santims.
char input[32]; // = "100;200;first";
char name[10];
int min, max, c, i, k;
FILE *file;
file = fopen("gg.txt","r");
i=0;
while ((c=getc(file))!= EOF)
{
k=(int)c;
input[i]=k;
i++;
}
char* result = NULL;
char delims[] = ";";
result = strtok(input, delims);
// atoi() converts ascii to integer.
min = atoi(result);
result = strtok(NULL, delims);
max = atoi(result);
result = strtok(NULL, delims);
strcpy(name, result);
printf("Min=%d, Max=%d, Name=%s\n", min, max, name);
printf("input=%s\n",input);
printf("%d\n",i);
getch();
return 0;
this code given me by varunl works vith smal numbers ( the containing of gg.txt file is: 100;200;first), but a need smt else, enybody, can help me?

Answer 1

The trick is in padding the numbers to 16 digits, so you can compare them as strings. So if you read this:
67000000;67999999;MAESTRO;
in reality you have to consider it like this:
0000000067000000;0000000067999999;MAESTRO;
The same for the user input.
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
void FindCCType(const char *pnumber);
int main(int argc, char *argv[])
{
FindCCType("67000001");
return 0;
}
#define MAXLENGTH 16
char* PadLeft(const char *pnumber)
{
char *pnumber2 = (char*)malloc(MAXLENGTH + 1);
size_t len = strlen(pnumber);
if (len > MAXLENGTH)
{
/* Too many digits in credit card number */
exit(1);
}
strcpy(pnumber2 + MAXLENGTH - len, pnumber);
char *pbegin = pnumber2, *plast = pnumber2 + MAXLENGTH - len;
while (pbegin < plast)
{
*pbegin = '0';
pbegin++;
}
return pnumber2;
}
void FindCCType(const char *pnumber)
{
printf("Input: %s\n", pnumber);
char *pnumber2 = PadLeft(pnumber);
FILE *file = fopen("gg.txt","r");
char pline[1000];
while (fgets(pline, sizeof(pline), file) != NULL)
{
if (strlen(pline) + 1 == sizeof(pline))
{
/* Line too much long */
exit(2);
}
char *pmin = strtok(pline, ";");
char *pmax = strtok(NULL, ";");
char *pname = strtok(NULL, ";");
printf("Min: %s, Max: %s, Name: %s", pmin, pmax, pname);
char *pmin2 = PadLeft(pmin);
char *pmax2 = PadLeft(pmax);
if (strcmp(pnumber2, pmin2) >= 0 && strcmp(pnumber2, pmax2) <= 0)
{
printf(" ** FOUND **\n");
free(pmin2);
free(pmax2);
break;
}
printf(" ** NO GOOD **\n");
free(pmin2);
free(pmax2);
}
fclose(file);
free(pnumber2);
}