Question

我正在编写多键快速排序，我编译得很好，但是当我运行时，停止工作异常，我认为它永远循环或类似的东西，我怎么能解决这个问题？再次编译时没有问题，这里是链接它 http://ideone.com/bBtaX

它写了运行时错误，这里也是代码

#include<stdlib.h>
#include<stdio.h>
#include<string.h>
#include<iostream>

using namespace std;

int min(int a,int b){
    return a<=b?a:b;
}

#define swap(a,b){ char *t=x[a];x[a]=x[b];x[b]=t;}
#define i2c(i)  x[i][depth]

void vecswap(int i, int j, int n, char *x[])
{ 
    while (n-- > 0) {
        swap(i, j);
        i++;
        j++;
    }
}

void ssort1(char *x[],int n,int depth);

void  ssort(char *x[],int n)
{
    ssort1(x,n,0);
}

void ssort1(char *x[],int n,int depth){
    int a,b,c,d,r,v;
    if(n<=1)
        return ;
    a=rand()%n;
    swap(0,a);
    v=i2c(0);
    a=b=1;
    c=d=n-1;
    for (;;)
    {
        while(b<=c && (r=i2c(b)-v)<=0){
            if (r==0) { 
                swap(a,b);a++;
            }
            b++;
        }

        while(b<=c && (r=i2c(c)-v)>=0){
            if (r==0) { 
                swap(c,d); d--;
            }
            c--;
        }

        if (b>c)  
            break;
        swap(b,c);
        b++;
        c--;
    }
    r=min(a,b-a);
    vecswap(0,b-r,r,x);
    r = min(d-c, n-d-1); 
    vecswap(b, n-r, r, x);
    r=b-a;
    ssort1(x,r,depth);
    if (i2c(r)!=0)
        ssort1(x+r,a+n-d-1,depth+1);
    r=d-c; 
    ssort1(x+n-r,r,depth);
}

int main(){
    char *s[]={"dato","giorgi","beso","computer","deda","kata","spilo"};
    int n=sizeof(s)/sizeof(char);

    ssort(s,n);
    for (int i=0;i<n;i++)
        cout<<s[i]<<"  "<<endl;
    return 0;
}

Answer 1

此：

int n=sizeof(s)/sizeof(char); /* Would return 28, resulting in out of bounds
                                 on array 's' in subsequent for loop. */

应该是：

int n=sizeof(s)/sizeof(char*);
                           ^

确定数组中元素数量的更安全的方法是：

int n=sizeof(s)/sizeof(s[0]);

多键快速排序崩溃

1 个答案: