How to convert Hexadecimal to Decimal in C++

In this article, we are going to learn How to convert Hexadecimal to Decimal in C++. Here we are going to learn about two number systems one is Decimal and another is Hexadecimal. Hexadecimal numbers are base 16 numbers and represented in numbers from 0 to 9 and A to F.Decimal numbers are base 10 numbers and represented in numbers from 0 to 9.

How to convert Hexadecimal to Decimal

In this C++ program to convert Hexadecimal to Decimal, we have custom code without using any built-in function

```#include<iostream>
#include <math.h>
#include <string.h>

using namespace std;

int main()
{
char hexNum[17];
long long decimalNum, place;
int val, len;

decimalNum = 0;
place = 1;

cout << "Please enter a Hexadecimal Number: ";
cin >> hexNum;

len = strlen(hexNum);
len--;

for(int i=0; hexNum[i] != '#include<iostream>
#include <math.h>
#include <string.h>
using namespace std;
int main()
{
char hexNum[17];
long long decimalNum, place;
int val, len;
decimalNum = 0;
place = 1;
cout << "Please enter a Hexadecimal Number: ";
cin >> hexNum;
len = strlen(hexNum);
len--;
for(int i=0; hexNum[i] != '\0'; i++)
{
if(hexNum[i]>='0' && hexNum[i]<='9')
{
val = hexNum[i] - 48;
}
else if(hexNum[i]>='a' && hexNum[i]<='f')
{
val = hexNum[i] - 97 + 10;
}
else if(hexNum[i]>='A' && hexNum[i]<='F')
{
val = hexNum[i] - 65 + 10;
}
decimalNum += val * pow(16, len);
len--;
}
cout << "\nThe Decimal equivalent of HexaDecimal number " <<  hexNum << " is " << decimalNum;
return 0;
}
'; i++)
{
if(hexNum[i]>='0' && hexNum[i]<='9')
{
val = hexNum[i] - 48;
}
else if(hexNum[i]>='a' && hexNum[i]<='f')
{
val = hexNum[i] - 97 + 10;
}
else if(hexNum[i]>='A' && hexNum[i]<='F')
{
val = hexNum[i] - 65 + 10;
}

decimalNum += val * pow(16, len);
len--;
}

cout << "\nThe Decimal equivalent of HexaDecimal number " <<  hexNum << " is " << decimalNum;

return 0;
}

```