c语言函数指针
1 #include <stdio.h> 2 typedef void (*intFunc)(int i); 3 4 void test1(int age) 5 { 6 printf("test1:%d\n",age); 7 } 8 int test2(char *str,int i) 9 { 10 } 11 void foreachNums(int *nums,int len,intFunc func) 12 { 13 int i; 14 for(i=0;i<len;i++) 15 { 16 int n = nums[i];//*(nums+i) 17 func(n); 18 } 19 } 20 void printIt(int i) 21 { 22 printf("value=%d\n",i); 23 } 24 void print100(int i) 25 { 26 printf("value=%d\n",i+100); 27 } 28 int main(int argc, char *argv[]) 29 { 30 //intFunc f1 = test1;//intFunc类型的函数指针指向test1函数 31 //f1(8);//执行f1函数指针指向的代码 32 //intFunc f2 = test2; 33 int nums[]={1,5,666,23423,223}; 34 //foreachNums(nums,sizeof(nums)/sizeof(int),printIt); 35 foreachNums(nums, 36 sizeof(nums)/sizeof(int),print100); 37 return 0; 38 }
http://www.rupeng.com/Segments/Index/1752
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1 #include <stdio.h> 2 3 //{3,5,8,7,6} 4 /* 5 int max(int *nums,int len) 6 { 7 int i; 8 int max=nums[0];//假定第0个元素为最大值 9 for(i=1;i<len;i++) 10 { 11 int value = *nums; 12 if(value>max) 13 { 14 max = value;//如果找到比max还大的，则max让位 15 } 16 nums++; 17 } 18 return max; 19 } 20 */ 21 22 typedef struct _Dog 23 { 24 char* name; 25 int age; 26 } Dog; 27 typedef int (*compareFunc)(void * data1,void * data2); 28 //data 待比较数据数组的首地址,uniteSize单元字节个数 29 //size：数据的长度。{1,3,5,6}：size=4 30 //比较data1和data2指向的数据做比较， 31 //如果data1>data2，则返回正数 32 void* max(void* data,int unitSize,int size, 33 compareFunc func) 34 { 35 int i; 36 char *ptr = (char *)data; 37 char *max = ptr;//假定最开始的元素为最大值 38 for(i=1;i<size;i++) 39 { 40 char* item = ptr+i*unitSize;//计算第i个元素的首地址 41 if(func(item,max)>0)//如果item大于max 42 //到底取几个字节进行比较是func内部的事情 43 { 44 max = item; 45 } 46 } 47 return max;//最大值的首地址 48 } 49 50 //data1是第一个被比较数字的首地址 51 int intCompare(void* data1,void *data2) 52 { 53 int* ptr1 = (int*)data1; 54 int* ptr2 = (int*)data2; 55 int i1=*ptr1; 56 int i2=*ptr2; 57 return i1-i2; 58 } 59 60 int dogCompare(void* data1,void* data2) 61 { 62 Dog* dog1 = (Dog*)data1; 63 Dog* dog2 = (Dog*)data2; 64 return (dog1->age)-(dog2->age); 65 //return (dog2->age)-(dog1->age); 66 } 67 68 int main(int argc, char *argv[]) 69 { 70 /* 71 int nums[] = {3,5,8,7,6}; 72 int *pMax = (int *)max(nums,sizeof(int),sizeof(nums)/sizeof(int), 73 intCompare); 74 int max = *pMax; 75 printf("%d\n",max); 76 */ 77 /*Dog dogs[] ={{"沙皮",3},{"腊肠",10},{"哈士奇",5},{"京巴",8},{"大狗",2}};*/ 78 /*Dog *pDog = (Dog *)max(dogs,sizeof(Dog), 79 sizeof(dogs)/sizeof(Dog),dogCompare); 80 printf("%s=%d",pDog->name,pDog->age);*/ 81 /*qsort(dogs,sizeof(dogs)/sizeof(Dog),sizeof(Dog),dogCompare); 82 int i; 83 for(i=0;i<sizeof(dogs)/sizeof(Dog);i++) 84 { 85 Dog dog = dogs[i]; 86 printf("%s=%d|",dog.name,dog.age); 87 }*/ 88 int nums[] = {3,5,8,7,6}; 89 qsort(nums,sizeof(nums)/sizeof(int),sizeof(int), 90 intCompare); 91 int i; 92 for(i=0;i<sizeof(nums)/sizeof(int);i++) 93 { 94 int n = nums[i]; 95 printf("%d|",n); 96 } 97 98 return 0; 99 }
http://www.rupeng.com/Segments/Index/1754
