一、了解qsort函数 void qsort (void* base, // 1size_t num, // 2size_t size, // 3int (*compare)(const void* a,const void* b)); // 4// 1. base 表示的是数组首元素的地址,一般为数组名// 2. num 表示的是数组中元素的个数// 3. size 表示的数组中每个元素所占内存的字节大小// ...
compare( (void *) & elem1, (void *) & elem2 ); The routine compares the elements and returns one of the following values.Проширитабелу Compare function return value Description < 0 elem1 less than elem2 0 elem1 equivalent to elem2 > 0 elem1 greater than elem2The...
AI代码解释 1/* qsort example */2#include<stdio.h>/* printf */3#include<stdlib.h>/* qsort */45int values[]={40,10,100,90,20,25};67intcompare(constvoid*a,constvoid*b)8{9return(*(int*)a-*(int*)b);10}1112intmain()13{14int n;15qsort(values,6,sizeof(int),compare);16for(...
// Comparing function: // Returns a positive number if a is greater than b // Returns a negative number if a is less than b // Returns 0 if a is equal to b int compare(const void *a, const void *b) { int *valA = a; int *valB = b; return *valA - *valB; } int main...
int comp(const void *a,const void *b) { return ((int *)a)[2]-((int *)b)[2]; // 交换依据,比较某两个元素 } // 以a为起始地址指针,根据compare结果决定起始位置往后sizeof(int)*2这一整块拷贝交换,也即整行交换 qsort(a,1000,sizeof(int)*50,comp); 例三:结构体比值 // @example....
qsort的compare函数原型 //comp ,也就说,如果the first < the second 返回-1,;如果the first > the second 返回1;如果the first == the second 返回0.,排序结果就表现为升序 comp-comparison function which returns a negative integer value if the first argument islessthan the second, ...
width:元素大小,单位是字节,待排序数组的单个元素的大小 cmp:函数指针(比较函数:compare function),比较两个元素的函数的地址 解释:对于不同类型元素的比较的方法是不同的,此处就是将两个元素的比较方法写成函数,传到qsort函数中,然后使用指针cmp进行调用
Example : How qsort() function works? #include <iostream> #include <cstdlib> using namespace std; int compare(const void* a, const void* b) { const int* x = (int*) a; const int* y = (int*) b; if (*x > *y) return 1; else if (*x < *y) return -1; return 0; } in...
/* Comparison function. Receives two generic (void) pointers to the items under comparison. */ intcompare_ints(constvoid*p,constvoid*q){ intx = *(constint*)p; inty = *(constint*)q; /* Avoid return x - y, which can cause undefined behaviour ...
Pointer to a function that compares two elements. This function is called repeatedly byqsortto compare two elements. It shall follow the following prototype: intcompar (constvoid* p1,constvoid* p2); Taking two pointers as arguments (both converted toconst void*). The function defines the order...