c语言函数指针

 #include <stdio.h>
 typedef void (*intFunc)(int i);

 void test1(int age)
 {
     printf("test1:%d\n",age);
 }
 int test2(char *str,int i)
 {
 }
 void foreachNums(int *nums,int len,intFunc func)
 {
     int i;
     for(i=;i<len;i++)
     {
         int n = nums[i];//*(nums+i)
         func(n);
     }
 }
 void printIt(int i)
 {
     printf("value=%d\n",i);
 }
 void print100(int i)
 {
     printf("value=%d\n",i+);
 }
 int main(int argc, char *argv[])
 {
     //intFunc f1 = test1;//intFunc类型的函数指针指向test1函数
     //f1(8);//执行f1函数指针指向的代码
     //intFunc f2 = test2;
     int nums[]={,,,,};
     //foreachNums(nums,sizeof(nums)/sizeof(int),printIt);
     foreachNums(nums,
         sizeof(nums)/sizeof(int),print100);
     return ;
 }

http://www.rupeng.com/Segments/Index/1752

-----------------------------------------------------

 #include <stdio.h>

 //{3,5,8,7,6}
 /*
 int max(int *nums,int len)
 {
     int i;
     int max=nums[0];//假定第0个元素为最大值
     for(i=1;i<len;i++)
     {
         int value = *nums;
         if(value>max)
         {
             max = value;//如果找到比max还大的，则max让位
         }
         nums++;
     }
     return max;
 }
 */

 typedef struct _Dog
 {
     char* name;
     int age;
 } Dog;
 typedef int (*compareFunc)(void * data1,void * data2);
 //data 待比较数据数组的首地址,uniteSize单元字节个数
 //size：数据的长度。{1,3,5,6}：size=4
 //比较data1和data2指向的数据做比较，
 //如果data1>data2，则返回正数
 void* max(void* data,int unitSize,int size,
     compareFunc func)
 {
     int i;
     char *ptr = (char *)data;
     char *max = ptr;//假定最开始的元素为最大值
     for(i=;i<size;i++)
     {
         char* item = ptr+i*unitSize;//计算第i个元素的首地址
         if(func(item,max)>)//如果item大于max
         //到底取几个字节进行比较是func内部的事情
         {
             max = item;
         }
     }
     return max;//最大值的首地址
 }

 //data1是第一个被比较数字的首地址
 int intCompare(void* data1,void *data2)
 {
     int* ptr1 = (int*)data1;
     int* ptr2 = (int*)data2;
     int i1=*ptr1;
     int i2=*ptr2;
     return i1-i2;
 }

 int dogCompare(void* data1,void* data2)
 {
     Dog* dog1 = (Dog*)data1;
     Dog* dog2 = (Dog*)data2;
     return (dog1->age)-(dog2->age);
     //return (dog2->age)-(dog1->age);
 }

 int main(int argc, char *argv[])
 {
     /*
     int nums[] = {3,5,8,7,6};
     int *pMax = (int *)max(nums,sizeof(int),sizeof(nums)/sizeof(int),
         intCompare);
     int max = *pMax;
     printf("%d\n",max);
     */
     /*Dog dogs[] ={{"沙皮",3},{"腊肠",10},{"哈士奇",5},{"京巴",8},{"大狗",2}};*/
     /*Dog *pDog = (Dog *)max(dogs,sizeof(Dog),
         sizeof(dogs)/sizeof(Dog),dogCompare);
     printf("%s=%d",pDog->name,pDog->age);*/
     /*qsort(dogs,sizeof(dogs)/sizeof(Dog),sizeof(Dog),dogCompare);
     int i;
     for(i=0;i<sizeof(dogs)/sizeof(Dog);i++)
     {
         Dog dog = dogs[i];
         printf("%s=%d|",dog.name,dog.age);
     }*/
     int nums[] = {,,,,};
     qsort(nums,sizeof(nums)/sizeof(int),sizeof(int),
         intCompare);
     int i;
     for(i=;i<sizeof(nums)/sizeof(int);i++)
     {
         int n = nums[i];
         printf("%d|",n);
     }

     return ;
 }

http://www.rupeng.com/Segments/Index/1754