Given a positive decimal number, find the simple exponential notation (x = a·10^b) of the given number.

Examples:

Input : 100.0 Output : 1E2 Explanation: The exponential notation of 100.0 is 1E2. Input :19 Output :1.9E1 Explanation: The exponential notation of 16 is 1.6E1.

**Approach:**

The simplest way is to find the position of the first non zero digit and the position of the dot. The difference between that positions is the value of b (if the value is positive you should also decrease it by one).

Below is the implementation of the above approach:

`// C++ code to find the exponential notation ` `#include <bits/stdc++.h> ` `using` `namespace` `std; ` ` ` `// function to calculate the exponential ` `// notation ` `void` `FindExponent(` `char` `s[], ` `int` `n) ` `{ ` ` ` `int` `i, j, b, c; ` ` ` `for` `(i = 0; s[i] == ` `'0'` `|| s[i] == ` `'.'` `; i++) ` ` ` `; ` ` ` `for` `(j = n - 1; s[j] == ` `'0'` `|| s[j] == ` `'.'` `; j--) ` ` ` `; ` ` ` ` ` `c = find(s, s + n, ` `'.'` `) - s; ` ` ` `putchar` `(s[i]); ` ` ` ` ` `if` `(i != j) ` ` ` `putchar` `(` `'.'` `); ` ` ` ` ` `for` `(` `int` `k = i + 1; k <= j; k++) ` ` ` `if` `(s[k] != ` `'.'` `) ` ` ` `putchar` `(s[k]); ` ` ` `if` `(i < c) ` ` ` `b = c - i - 1; ` ` ` `else` ` ` `b = c - i; ` ` ` `if` `(b) ` ` ` `printf` `(` `"E%d"` `, b); ` `} ` ` ` `// main function ` `int` `main() ` `{ ` ` ` `char` `s[] = ` `"100"` `; ` ` ` `int` `n = ` `strlen` `(s); ` ` ` `FindExponent(s, n); ` `} ` |

*chevron_right*

*filter_none*

Output:

1E2

## Recommended Posts:

- Write a program to reverse digits of a number
- Write an Efficient Method to Check if a Number is Multiple of 3
- Write an Efficient C Program to Reverse Bits of a Number
- Minimum number of jumps to reach end
- Find minimum number to be divided to make a number a perfect square
- Find whether a given number is a power of 4 or not
- Print all combinations of points that can compose a given number
- Check if a number is multiple of 5 without using / and % operators
- Given a number, find the next smallest palindrome
- Count the number of possible triangles
- Select a random number from stream, with O(1) space
- Program to convert a given number to words
- Efficient program to print all prime factors of a given number
- Check if a number is Palindrome
- Random number generator in arbitrary probability distribution fashion

If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.