第一种方法:使用字符串来代表数字,实现数值相加进位
第二种方法:使用递归来实现全排列
#include <iostream>
using namespace std;
bool Increment(char* number);
void PrintNumber(char* number);
void Print1ToMaxOfNDigits(int n) {
if (n <= 0)
return;
char* number = new char[n + 1];
memset(number, '0', n);
number[n] = '\0';
while (!Increment(number)) {
PrintNumber(number);
}
}
//通过进位来判断是否到了最大的n位数
bool Increment(char* number) {
bool isOverflow = false;
int nTakeOver = 0;
int nLength = strlen(number);
for (int i = nLength - 1; i >= 0; i--) {
int nSum = number[i] - '0' + nTakeOver;
if (i == nLength - 1)
nSum++;
if (nSum >= 10) {
if (i == 0)
isOverflow = true;
else {
nSum -= 10;
nTakeOver = 1;
number[i] = '0' + nSum;
}
}
else {
number[i] = '0' + nSum;
break;
}
}
return isOverflow;
}
//打印输出
void PrintNumber(char* number) {
bool isBeginning0 = true;
int nLength = strlen(number);
for (int i = 0; i < nLength; ++i) {
if (isBeginning0 && number[i] != '0') {
isBeginning0 = false;
}
if (!isBeginning0)
printf("%c", number[i]);
}
printf("\t");
}
int main() {
Print1ToMaxOfNDigits(3);
getchar();
return 0;
}
#include <iostream>
using namespace std;
void PrintNumber(char* number);
void Print1ToMaxOfNDigitsRecursively(char* number, int length, int index);
void Print1ToMaxOfNDigits(int n) {
if (n <= 0)
return;
char* number = new char[n + 1];
number[n] = '\0';
for (int i = 0; i < 10; ++i) {
number[0] = i + '0';
Print1ToMaxOfNDigitsRecursively(number, n, 0);
}
delete[] number;
}
void Print1ToMaxOfNDigitsRecursively(char* number, int length, int index) {
if (index == length - 1) {
PrintNumber(number);
return;
}
for (int i = 0; i < 10; ++i) {
number[index + 1] = i + '0';
Print1ToMaxOfNDigitsRecursively(number, length, index + 1);
}
}
//打印输出
void PrintNumber(char* number) {
bool isBeginning0 = true;
int nLength = strlen(number);
for (int i = 0; i < nLength; ++i) {
if (isBeginning0 && number[i] != '0') {
isBeginning0 = false;
}
if (!isBeginning0)
printf("%c", number[i]);
}
printf("\t");
}
int main() {
Print1ToMaxOfNDigits(3);
getchar();
return 0;
}