Example
Input
Input hexadecimal: 1A
Output
Decimal number: 26
Logic to convert Hexadecimal to Decimal
/**
* C program to convert Hexadecimal to Decimal number system
*/
#include <stdio.h>
#include <math.h>
#include <string.h>
int main()
{
char hex[17];
long long decimal, place;
int i = 0, val, len;
decimal = 0;
place = 1;
/* Input hexadecimal number from user */
printf("Enter any hexadecimal number: ");
gets(hex);
/* Find the length of total number of hex digit */
len = strlen(hex);
len--;
/*
* Iterate over each hex digit
*/
for(i=0; hex[i]!='\0'; i++)
{
/* Find the decimal representation of hex[i] */
if(hex[i]>='0' && hex[i]<='9')
{
val = hex[i] - 48;
}
else if(hex[i]>='a' && hex[i]<='f')
{
val = hex[i] - 97 + 10;
}
else if(hex[i]>='A' && hex[i]<='F')
{
val = hex[i] - 65 + 10;
}
decimal += val * pow(16, len);
len--;
}
printf("Hexadecimal number = %s\n", hex);
printf("Decimal number = %lld", decimal);
return 0;
}
/*
Output :
Enter any hexadecimal number: 1a
Hexadecimal number = 1a
Decimal number = 26
*/