# Find Column Name from Column Number in Excel using C++

Today, we are gonna write a simple C++ program to find Column Name from Column Number in Excel sheets.

The rows in an excel sheet are numbered with values starting from 1, 2, 3,….., and so on.

The columns, however, are identified with their character names. These start from A, B,………, Y, Z, AA, AB,……., AY, AZ, BA, BB,………, and so on. For example,

 Column Number Column Name 26 Z 51 AY 80 CB 702 ZZ 705 AAC

## Algorithm to get Column Name from Column Number

1. Let us suppose that the user has entered a number num, which is 28, for which we have to find the corresponding column name.
2. We need to take the remainder of num, 28 here, with 26.
3. If the remainder comes out to be 0 (for numbers like 26, 52, 78,…etc.), then we insert ‘Z’ in the char array that we made for storing the output string.
4. Simultaneously, the new num now is updated to num/26 -1, because here assuming that 26 is ‘Z’ while in reality ‘Z’ is 25th with respect to the letter ‘A’.
5. Otherwise, if the remainder is non-zero. (like 1, 2, ……, 24, 25), then we just insert the letter accordingly in the char array.
6. And simultaneously, update num = num/26.
7. To print the finally answer, we reverse the string and display it.

## C++ code to get Column Name from Column Number in Excel

```#include <bits/stdc++.h>
#include<iostream>
using namespace std;

//function to display the column name form column number
void Convert_to_Column_Name(int num)
{
//variables used
//array to store column name after conversion
char name;
int i = 0;

//iterating loop
while(num > 0)
{
//remainder after dividing number by 26 is stored
int remainder = num%26;

//if else condition to store appropriate alphabets
if(remainder == 0)
{
name[i++] = 'Z';
num = (num/26) - 1;
}
else
{
name[i++] = (remainder-1) + 'A';
num = num/26;
}
}

//storing '\0' at the end of the string
name[i] = '\0';

//we use the library function to reverse the string
reverse(name, name + strlen(name));

//display the result
cout<<name;

return;
}

//int main/Driver program
int main()
{
//variable to store the column number
int num;

//taking the input from the user
cout<<"Enter column number for which you want the column name: ";
cin>>num;

//checking for valid input
if(num > 0)
{
//calling the function for conversion and displaying result
cout<<"\nThe column name for column number "<<num<<" is: ";
Convert_to_Column_Name(num);
}
else
{
cout<<"\nInvalid input!";
}

return 0;
}```

#### Output

• 1 – Character Input
```Enter column number for which you want the column name: cghf

Invalid input!```
• 2 – Negative Input
```Enter column number for which you want the column name: -85

Invalid input!
```
• 3 – Zero Input
```Enter column number for which you want the column name: 0

Invalid input!```
• 4 – Positive/Valid Input
```Enter column number for which you want the column name: 702

The column name for column number 702 is: ZZ```