Method 1:::::
/* Written by Prakash Katudia
Compile it with below command
"gcc -lm hexToDec.c"
*/
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<math.h>
int main(){
char str[10],ch;
int a[255], b[256],len,i,k,j=0,num,rem=0,dec=0;
printf("Enter hex number\n");
scanf("%s",str);
len = strlen(str);
for(i=len-1;i>=0;i--)
{
/* take a case for A,B,C,D,E,F hex num */
ch=str[i],k=0;
switch(ch)
{
case 'A':
num = 10;
break;
case 'B':
num = 11;
break;
case 'C':
num = 12;
break;
case 'D':
num = 13;
break;
case 'E':
num = 14;
break;
case 'F':
num = 15;
break;
default :
num = str[i] - '0';
}
/* store in array in binary */
while(k<=3){
if(num!=0){
rem = num%2;
a[j] = rem;
num = num/2;
}
else
a[j] = 0;
j++;k++;
}
}
printf("Binary of given hex code is= ");
/* print binary and convert it into decimal as well */
for(i=j-1;i>=0;i--)
{
printf("%d",a[i]);
dec = dec + (a[i]*pow(2,i));
}
printf("\nDecimal of given hex is = %d \n",dec);
return 0;
}
Method 2:
#include <stdio.h>
int main()
{
char s[] = "FF";
int x;
sscanf(s, "%x", &x);
printf("%u\n", x);
return 0;
}
