C/C++ 数字数组转换为一个整数

阳光穿透心脏的1/2处 2022-11-07 11:46 153阅读 0赞

# **C/C++ 数字数组转换为一个整数** #

## 1. Description ##

数字数组转换为一个整数，数字由 0 ~ 9 组成。

For example:  
input:

const int N = 5;
    	const int data_array_1[5] = { 1, 2, 3, 4, 5 };

output: `12345`

{ 1,   2,   3,   4,   5 }  - array
      0    1    2    3    4    - idx
      10^4 10^3 10^2 10^1 10^0 - weight

## 2. Yongqiang ##

{ 1, 2, 3, 4, 5 } -> 12345
    { 1, 2, 0, 4, 5 } -> 12045
    请按任意键继续. . .

## 3. Master ##

//============================================================================
    // Name        : Yongqiang Cheng
    // Author      : Yongqiang Cheng
    // Version     : Version 1.0.0
    // Copyright   : Copyright (c) 2020 Yongqiang Cheng
    // Description : Hello World in C++, Ansi-style
    //============================================================================
    
    #ifndef _CRT_SECURE_NO_WARNINGS
    #define _CRT_SECURE_NO_WARNINGS
    #endif
    
    #include <iostream>
    
    long long array_to_number(const int N, const int *data_array)
    {
    	long long number = 0;
    	long long weight = 1;
    	for (register int i = N - 1; i >= 0; --i)
    	{
    		number += data_array[i] * weight;
    		weight *= 10;
    	}
    
    	return number;
    }
    
    long long array_to_number_master(const int N, const int *data_array)
    {
    	long long number = 0;
    	for (register int i = 0; i < N; ++i)
    	{
    		number = number * 10 + data_array[i];
    	}
    
    	return number;
    }
    
    int main()
    {
    	const int N = 5;
    	const int data_array_1[5] = { 1, 2, 3, 4, 5 };
    	long long number_1 = array_to_number(N, data_array_1);
    	std::cout << "{ 1, 2, 3, 4, 5 } -> " << number_1 << std::endl;
    
    	const int data_array_2[5] = { 1, 2, 0, 4, 5 };
    	long long number_2 = array_to_number(N, data_array_2);
    	std::cout << "{ 1, 2, 0, 4, 5 } -> " << number_2 << std::endl << std::endl;
    
    	const int data_array_3[5] = { 1, 2, 3, 4, 5 };
    	long long number_3 = array_to_number_master(N, data_array_3);
    	std::cout << "{ 1, 2, 3, 4, 5 } -> " << number_3 << std::endl;
    
    	const int data_array_4[5] = { 1, 2, 0, 4, 5 };
    	long long number_4 = array_to_number_master(N, data_array_4);
    	std::cout << "{ 1, 2, 0, 4, 5 } -> " << number_4 << std::endl;
    
    	const int data_array_5[5] = { 2, 6, 1, 8, 4 };
    	long long number_5 = array_to_number_master(N, data_array_5);
    	std::cout << "{ 2, 6, 1, 8, 4 } -> " << number_5 << std::endl;
    
    	return 0;
    }

{ 1, 2, 3, 4, 5 } -> 12345
    { 1, 2, 0, 4, 5 } -> 12045
    
    { 1, 2, 3, 4, 5 } -> 12345
    { 1, 2, 0, 4, 5 } -> 12045
    { 2, 6, 1, 8, 4 } -> 26184
    请按任意键继续. . .