查找数字的第一位和最后一位

给定一个数字并查找数字的第一位和最后一位。
例子：

Input : 12345 
Output : First digit: 1
         last digit : 5

Input : 98562
Output : First digit: 9
         last digit : 2

要查找数字的最后一位，我们使用模运算符％ 。当取10的模数时，返回其最后一位。
假设n = 1234
然后最后一位= n％10 => 4
查找数字的第一个数字比最后一个数字便宜。为了找到数字的第一位数字，我们将给定的数字除以10，直到数字大于10。最后，我们剩下第一位数字。

方法1(带循环)：

C++

// Program to find first and last
// digits of a number
#include 
using namespace std;
 
// Find the first digit
int firstDigit(int n)
{
    // Remove last digit from number
    // till only one digit is left
    while (n >= 10)
        n /= 10;
     
    // return the first digit
    return n;
}
 
// Find the last digit
int lastDigit(int n)
{
    // return the last digit
    return (n % 10);
}
 
// Driver program
int main()
{
    int n = 98562;
    cout << firstDigit(n) << " "
        << lastDigit(n) << endl;
    return 0;
}

Java

// Java Program to find first and last
// digits of a number
import java.util.*;
import java.lang.*;
 
public class GfG{
     
    // Find the first digit
    public static int firstDigit(int n)
    {
        // Remove last digit from number
        // till only one digit is left
        while (n >= 10)
            n /= 10;
     
        // return the first digit
        return n;
    }
 
    // Find the last digit
    public static int lastDigit(int n)
    {
        // return the last digit
        return (n % 10);
    }
     
    // driver function
    public static void main(String argc[])
    {
        int n = 98562;
        System.out.println(firstDigit(n) + " "
        + lastDigit(n));
    }
}
 
// This code is contributed by Sagar Shukla

Python3

# Python3 program to find first and
# last digits of a number
 
# Find the first digit
def firstDigit(n) :
 
    # Remove last digit from number
    # till only one digit is left
    while n >= 10:
        n = n / 10;
     
    # return the first digit
    return int(n)
 
# Find the last digit
def lastDigit(n) :
 
    # return the last digit
    return (n % 10)
 
# Driver Code
n = 98562;
print(firstDigit(n), end = " ")
print(lastDigit(n))
 
# This code is contributed by rishabh_jain

C#

// C# Program to find first and last
// digits of a number
using System;
 
public class GfG{
     
    // Find the first digit
    public static int firstDigit(int n)
    {
        // Remove last digit from number
        // till only one digit is left
        while (n >= 10)
            n /= 10;
     
        // return the first digit
        return n;
    }
 
    // Find the last digit
    public static int lastDigit(int n)
    {
        // return the last digit
        return (n % 10);
    }
     
    // driver function
    public static void Main()
    {
        int n = 98562;
        Console.WriteLine(firstDigit(n) + " "
        + lastDigit(n));
    }
}
 
// This code is contributed by vt_m

PHP

= 10)
        $n /= 10;
     
    // return the first digit
    return (int)$n;
}
 
// Find the last digit
function lastDigit($n)
{
    // return the last digit
    return ((int)$n % 10);
}
 
// Driver Code
$n = 98562;
echo firstDigit($n) . " " .
     lastDigit($n) . "\n";
 
// This code is contributed
// by Akanksha Rai(Abby_akku)

Javascript

// javascript Program to find first and last
// digits of a number
 
    // Find the first digit
    function firstDigit(n)
    {
        // Remove last digit from number
        // till only one digit is left
        while (n >= 10)
            n /= 10;
       
        // return the first digit
        return Math.floor(n);
    }
   
    // Find the last digit
    function lastDigit(n)
    {
        // return the last digit
        return Math.floor(n % 10);
    }
 
// Driver code
 
         let n = 98562;
        document.write(firstDigit(n) + " "
        + lastDigit(n));
  
 // This code is contributed by sanjoy_62.

输出：

9 2

方法2(无循环)

C++

// Program to find first and last
// digits of a number
#include 
using namespace std;
 
// Find the first digit
int firstDigit(int n)
{
    // Find total number of digits - 1
    int digits = (int)log10(n);
 
    // Find first digit
    n = (int)(n / pow(10, digits));
 
    // Return first digit
    return n;
}
 
// Find the last digit
int lastDigit(int n)
{
    // return the last digit
    return (n % 10);
}
 
// Driver program
int main()
{
    int n = 98562;
    cout << firstDigit(n) << " "
         << lastDigit(n) << endl;
    return 0;
}

Java

// Java program to find first and
// last  digits of a number
import java.math.*;
 
class GFG {
     
    // Find the first digit
    static int firstDigit(int n)
    {
        // Find total number of digits - 1
        int digits = (int)(Math.log10(n));
     
        // Find first digit
        n = (int)(n / (int)(Math.pow(10, digits)));
     
        // Return first digit
        return n;
    }
     
    // Find the last digit
    static int lastDigit(int n)
    {
        // return the last digit
        return (n % 10);
    }
     
    // Driver program
    public static void main(String args[])
    {
        int n = 98562;
        System.out.println(firstDigit(n) +
                           " " + lastDigit(n));
    }
}
 
 
// This code is contributed by Nikita Tiwari.

Python3

# Python3 program to find first 
# and last digits of a number
import math
 
# Find the first digit
def firstDigit(n) :
     
    # Find total number of digits - 1
    digits = (int)(math.log10(n))
 
    # Find first digit
    n = (int)(n / pow(10, digits))
 
    # Return first digit
    return n;
 
# Find the last digit
def lastDigit(n) :
     
    # return the last digit
    return (n % 10)
 
# Driver Code
n = 98562;
print(firstDigit(n), end = " ")
print(lastDigit(n))
 
# This code is contributed by rishabh_jain

C＃

// C# program to find first and
// last digits of a number
using System;
 
class GFG {
     
    // Find the first digit
    static int firstDigit(int n)
    {
        // Find total number of digits - 1
        int digits = (int)(Math.Log10(n));
     
        // Find first digit
        n = (int)(n / (int)(Math.Pow(10, digits)));
     
        // Return first digit
        return n;
    }
     
    // Find the last digit
    static int lastDigit(int n)
    {
        // return the last digit
        return (n % 10);
    }
     
    // Driver program
    public static void Main()
    {
        int n = 98562;
        Console.WriteLine(firstDigit(n) +
                        " " + lastDigit(n));
    }
}
 
 
// This code is contributed by vt_m.

输出：

9 2

重要说明： log10()是math.h头文件中存在的数学函数。它将传递的参数的以10为底的日志值返回到log10()函数。