**/printf("在swap函数中:\n"); printf("指针x指向的地址为%p,值为%d,指针本身的地址为%p\n", x, *x, &x); printf("指针y指向的地址为%p,值为%d,指针本身的地址为%p\n", y, *y, &y);inttmp = *x;*x = *y;*y =tmp; }intmain(void) {intx =3, y =5; printf("在main函数中:\...
The void pointer, also known as the generic pointer, is a special type of pointer that can be pointed at objects of any data type! A void pointer is declared like a normal pointer, using the void keyword as the pointer’s type: #include<stdio.h> #define TRUE 1 #define FALSE 0 int ...
1.1 函数指针(Pointer to Function) 函数指针是一个指针,它指向函数的入口地址。 简单来说,就是用一个指针变量来保存函数的地址,通过这个指针可以间接地调用该函数。 如果是我们特训营学过项目3的老铁,应该非常熟悉了,我们大量回调函数的应用,就必须要用到函数指针。 1.2 指针函数(Function Returning Pointer) 指针...
理解C中的函数指针 ;// Function pointervoidtest1(intage){printf("test1:%d\n\n",age);}voidforeachNums(int*nums,intlen,intFunc func){inti;for(i=0; i<len; i++) {intnum = nums[i];func(num);// call the function through its pointer}}voidprintNum(intnum){printf("value=%d\n",num)...
函数指针(function pointer) 函数指针是一个指向函数的指针,例如void (*print)(PrintType *pt);。 切记,不能写成void *print(PrintType *pt);,仅仅是去掉了一个括号,这两者是有着天壤之别的。去掉括号代表了一个函数,它的返回类型是void *,拥有括号则是一个函数指针。
gfnPtr = *((FN_GET_VAL*) (&fnPointer)); } 文件2.c: extern FN_GET_VAL gfnPtr; unsigned long myfunc(void) { return 0; } main() { setCallback((void*)myfunc); gfnPtr(); /* Crashing as value was not properly assigned in setCallback function */ } 使用gcc编译时,gfnPtr()在64...
看左边,是void*,哦,原来是包含10个void*的数组。 that's it! 用英文更好理解,因为英文的从句可以让上面这么多步连成一整句话。 (middle) fp1 is → (right, nothing) → (left) a pointer to → (right) a function that takes an int → (left) and returns a pointer to → (right) an array ...
voidcompareNumberFunction(int*numberArray,intcount,intcompareNumber){for(inti=0;i<count;i++){if(*(numberArray+i)>compareNumber){printf("%d\n",*(numberArray+i));}}}intmain(){intnumberArray[5]={15,34,44,56,64};intcompareNumber=50;compareNumberFunction(numberArray,5,compareNumber);return...
int function_pointer_test_2(void) { int ret; int arg = 1; int i = 0; FUNCTION func = NULL; //定义个函数指针 FUNCTION func_array[] = //定义一组函数列表 { test_function_1, test_function_2, test_function_3, }; //终极大招,循环处理3个函数的间接调用 ...
利用typedef定義一個predicate型態的function pointer,傳入為int,傳出為int,雖然不一定得自行用typedef定義,但function pointer很容易寫成很複雜很難懂的程式,所以建議用typedef重新定義。 21行 void print_array(int *beg, int *end, predicate fn) { 宣告print_array最後一個參數為predicate這個function pointer型態,可...