#include "stdio.h"
#include "math.h"
#include <string.h>

int hex2dec(char * hex);
int check_32bit(char *input);
int main(){
	int str_len = 8;
	char input[str_len];
	printf("Please enter a hexadecimal value:");
	scanf("%s",input);

	if (check_32bit(input) == 0){
		printf("The decimal value of %s is %d\n",input,hex2dec(input));
	}
	else{
		printf("Sorry, We only handle 32 bit values :(\n");
	}



	return 0;
}
int check_32bit(char *input){
	if (strlen(input) <= 8){
		return 0;
	}
	else{
		return -1;
	}
}
int hex2dec(char * hex)
{
    //char hex[N];
    int length = strlen(hex);
    int i,j,n[length];
    int dec=0;
    for(i=0;i<length;i++)
    {
        switch(hex[i])
        {
        case '0':
            n[i]=hex[i]-48;     //Ascii code of 0 is 48  48-48=0//
            break;
        case '1':
            n[i]=hex[i]-48;  //Ascii code of 1 is 49  49-48=1//
            break;
        case '2':
            n[i]=hex[i]-48;  //Ascii code of 2 is 50  50-48=2//
            break;
        case '3':
            n[i]=hex[i]-48;  //Ascii code of 3 is 51  51-48=3//
            break;
        case '4':
            n[i]=hex[i]-48;  //Ascii code of 4 is 52  52-48=4//
            break;
        case '5':
            n[i]=hex[i]-48;  //Ascii code of 5 is 53  53-48=5//
            break;
        case '6':
            n[i]=hex[i]-48;  //Ascii code of 6 is 54  54-48=6//
            break;
        case '7':
            n[i]=hex[i]-48;  //Ascii code of 7 is 55  55-48=7//
            break;
        case '8':
            n[i]=hex[i]-48;  //Ascii code of 8 is 56  56-48=8//
            break;
        case '9':
            n[i]=hex[i]-48;  //Ascii code of 9 is 57  57-48=9//
            break;
        case 'A':
            n[i]=hex[i]-55;     //Ascii code of A is 65 65-55=10//
            break;
        case 'B':
            n[i]=hex[i]-55;  //Ascii code of B is 65 66-55=11//
            break;
        case 'C':
            n[i]=hex[i]-55;  //Ascii code of C is 65 67-55=12//
            break;
        case 'D':
            n[i]=hex[i]-55;  //Ascii code of D is 65 68-55=13//
            break;
        case 'E':
            n[i]=hex[i]-55;  //Ascii code of E is 65 68-55=14//
            break;
        case 'F':
            n[i]=hex[i]-55;  //Ascii code of F is 65 69-55=15//
            break;
        }
    }
    for(i=0,j=length;i<length;i++,j--)
        dec=dec+(n[j-1]*pow(16,i));
    return dec;
}