[C++] 打印从1到最大的n位数（string处理最大数）

以你之姓@ 2022-12-08 13:00 118阅读 0赞

/*------------------------------------*/
    /** * @file 剑指offer * @brief 输出从1到n的整数 * * @author DuYong * @date 2020-9-19 **/
    /*------------------------------------*/
    
    #define _CRT_SECURE_NO_WARNINGS
    #include <iostream>
    #include <string>
    #include <iomanip>
    
    using namespace std;
    
    // 1. 模拟数字加法
    void print1ToMaxOfNDigits1(size_t n);
    
    // 2. 使用递归排列组合
    void print1ToMaxOfNDigits2(size_t n);
    
    // string 模拟数字加法
    bool increment(string& number);
    
    // 格式化打印
    void printNumber(string number);
    
    void recursivelyPrint(string& number, int index);
    
    int main()
    { 
    
    	// print1ToMaxOfNDigits1(2);
    	print1ToMaxOfNDigits2(2);
    
    	system("pause");
    	return 0;
    }
    
    
    void recursivelyPrint(string& number, int index) { 
    	if (index == number.size() - 1) { 
    		printNumber(number);
    		return;
    	}
    
    	for (int i = 0; i < 10; i++) { 
    		number[index + 1] = i + '0';
    		recursivelyPrint(number, index + 1);
    	}
    }
    
    void print1ToMaxOfNDigits2(size_t n) { 
    	string number(n, '0');
    	for (int i = 0; i < 10; i++) { 
    		number[0] = i + '0';
    		recursivelyPrint(number, 0);
    	}
    }
    
    
    
    void print1ToMaxOfNDigits1(size_t n) { 
    
    	string number(n, '0');
    	size_t count = 0;
    
    	while (!increment(number)) { 
    		printNumber(number);
    		count++;
    		if (count % 10 == 0) { 
    			cout << endl;
    		}
    	}
    	cout << endl;
    }
    
    bool increment(string& number) { 
    	bool isOverflow = false;
    	size_t nTakeOver = 0;
    
    	for (int i = number.size() - 1; i >= 0; i--) { 
    		size_t nSum = number[i] - '0' + nTakeOver;
    		if (i == number.size() - 1) { 
    			nSum++;
    		}
    
    		if (nSum >= 10) { 
    			if (i == 0) { 
    				isOverflow = true;
    			}
    			else { 
    				nSum -= 10;
    				nTakeOver = 1;
    				number[i] = nSum + '0';
    			}
    		}
    		else { 
    			number[i] = nSum + '0';
    			break;
    		}
    	}
    
    	return isOverflow;
    }
    
    void printNumber(string number) { 
    	size_t i = 0;
    	while (number[i] == '0') { 
    		i++;
    	}
    
    	string tmpString = number.substr(i);
    	cout << setw(3) << tmpString << ',';
    }