【发布时间】：2014-02-09 22:03:30
【问题描述】：
我有一个家庭作业问题，我遇到了一些问题，我被要求使用 C++ 按字母顺序对 C 字符串数组进行排序，使用的排序算法必须是冒泡排序。到目前为止我所做的（复制如下）可以对数组进行排序，但仅基于第一个字母表。如何进一步对具有相同初始字母的字符串进行排序？
<snipped>@arch:~/College/OOP/Lab/W3$ cat 2.cpp
/*
* Write a function which sorts an array of C strings in ascending order using bubble sort. The
* number of strings in the array and the array must be passed as parameters to the function
*/
#include <iostream>
#include <cstring>
using namespace std;
void sort(char **sar, unsigned num, unsigned len)
{
char *temp = new char[len];
if (temp == NULL)
{
cout << "\nOut-Of-Memory\n";
return;
}
for (unsigned a = 0; a < num-1; a++)
{
for (unsigned b = 0; b < ((num-a)-1); b++)
{
if (sar[b][0] > sar[b+1][0])
{
strcpy(temp, sar[b]);
strcpy(sar[b], sar[b+1]);
strcpy(sar[b+1], temp);
}
}
}
delete[] temp;
}
int main(int argc, char *argv[])
{
char **sar;
unsigned num;
unsigned len;
cout << "Number of Strings: ";
cin >> num;
cout << "Length of Strings: ";
cin >> len;
cin.ignore(); // Flush buffer to fix a bug (getline after cin).
sar = (char **) new char*[num];
if (sar == NULL)
{
cout << "\nOut-Of-Memory\n";
return -1;
}
for (unsigned i = 0; i < num; i++)
{
sar[i] = (char *) new char[len];
if (sar[i] == NULL)
{
// Let's pretend we 'know' memory management
// because obviously modern OSs are incapable
// of reclaiming heap from a quitting process..
for (unsigned j = 0; j < i; j++)
delete[] sar[j];
cout << "\nOut-Of-Memory\n";
return -1;
}
}
for (unsigned x = 0; x < num; x++)
cin.getline(&sar[x][0], 512);
sort(sar, num, len);
cout << '\n';
for (unsigned y = 0; y < num; y++)
cout << sar[y] << '\n';
for (unsigned z = 0; z < num; z++)
delete[] sar[z];
delete[] sar;
return 0;
}
【问题讨论】：
-
delete的使用无效。你应该使用delete[]。 -
具体在哪里？ valgrind 不会对这样的事情咧嘴笑。
-
在您的排序功能中也是如此。接近尾声时，您在 temp 上致电
delete。应该是delete[]。 -
谢谢，但这对我的问题并没有真正的影响。很快就会更新。