# Convert Octal to Hexadecimal Program in C++

## C++ program to Convert Octal to Hexadecimal

To convert Octal number to Hexadecimal number in C++ programming, We have to ask to the user to enter the Octal number to convert it into Hexadecimal number to display the equivalent value in Hexadecimal format on screen.
When converting from octal to hexadecimal, it is often easier to first convert the octal number into binary and then from binary into hexadecimal.

## Hex / decimal / octal / binary conversion table

Hex Decimal Octal Binary
0 0 0 0
1 1 1 1
2 2 2 10
3 3 3 11
4 4 4 100
5 5 5 101
6 6 6 110
7 7 7 111
8 8 10 1000
9 9 11 1001
A 10 12 1010
B 11 13 1011
C 12 14 1100
D 13 15 1101
E 14 16 1110
F 15 17 1111
10 16 20 10000
20 32 40 100000
40 64 100 1000000
80 128 200 10000000
100 256 400 100000000
200 512 1000 1000000000
400 1024 2000 10000000000

## Example

```Input Octal Number : 10

Input Octal Number : 6

Input Octal Number : 11
```

## C++ program to convert Octal to Hexadecimal

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

int main()
{
int OCTALVALUES[] = {0, 1, 10, 11, 100, 101, 110, 111};

long long octal, temp_Octal, binary, place;
char hex[65] = "";
int rem;

place = 1;
binary = 0;
clrscr();

cout<<"Please Enter any Octal Number: ";
cin>>octal;
temp_Octal = octal;

// First Convert Octal to Binary

while(temp_Octal > 0)
{
rem = temp_Octal % 10;
binary = (OCTALVALUES[rem] * place) + binary;
temp_Octal /= 10;

place *= 1000;
}

while(binary > 0)
{
rem = binary % 10000;
switch(rem)
{
case 0:
strcat(hex, "0");
break;
case 1:
strcat(hex, "1");
break;
case 10:
strcat(hex, "2");
break;
case 11:
strcat(hex, "3");
break;
case 100:
strcat(hex, "4");
break;
case 101:
strcat(hex, "5");
break;
case 110:
strcat(hex, "6");
break;
case 111:
strcat(hex, "7");
break;
case 1000:
strcat(hex, "8");
break;
case 1001:
strcat(hex, "9");
break;
case 1010:
strcat(hex, "A");
break;
case 1011:
strcat(hex, "B");
break;
case 1100:
strcat(hex, "C");
break;
case 1101:
strcat(hex, "D");
break;
case 1110:
strcat(hex, "E");
break;
case 1111:
strcat(hex, "F");
break;
}

binary /= 10000;
}

strrev(hex);

cout<<" Equivalent Hexadecimal number: "<< hex;

getch();
}
```

## Output

```Enter any Octal Number: 15
```