北大 C++ 1.1 函数指针

函数指针：

eg.1

#include <stdio.h>void PrintSmall(int a,int b){    if(a<b) printf("%d\n",a);    else printf("%d\n",b);}int main(){    int x=4,y=5;    void (*pf)(int,int);    pf=PrintSmall;    pf(x,y);    return 0;}

eg.2

#include <stdio.h>#include <stdlib.h>int MyCompare(const void *elem1,const void *elem2){    unsigned int *p1,*p2;    p1 = (unsigned int *)elem1;    p2 = (unsigned int *)elem2;    return    ((*p1 % 10) - (*p2 % 10));}#define NUM 5int main(){    unsigned int an[NUM]={8,123,11,10,4};    qsort(an,NUM,sizeof(unsigned int),MyCompare);    for(int i=0;i<NUM;i++){        printf("%d\n",an[i]);    }    return 0;}