c语言指针接收数组的值（C数组指针函数指针做函数参数和返回值）

数组和函数不能用做参数和返回值，但数组指针和函数指针可以，我来为大家科普一下关于c语言指针接收数组的值?下面希望有你要的答案，我们一起来看看吧!

c语言指针接收数组的值

数组和函数不能用做参数和返回值，但数组指针和函数指针可以。

1 数组指针做函数参数

数组指针做函数参数，数组名用做实参时，其形参为指向数组首元素的指针（指针目标类型为数组元素）。

#include <stdio.h> #include <stdlib.h> #define ROWS 3 #define COLS 2 void fun1(int (*)[COLS], int); int main() { int array_2D[ROWS][COLS] = { {1, 2}, {3, 4}, {5, 6} }; int rows = ROWS; /* works here because array_2d is still in scope and still an array */ printf("MAIN: %zu\n",sizeof(array_2D)/sizeof(array_2D[0])); fun1(array_2D, rows); getchar(); return EXIT_SUCCESS; } void fun1(int (*a)[COLS], int rows) { int i, j; int n, m; n = rows; /* Works, because that information is passed (as "COLS"). It is also redundant because that value is known at compile time (in "COLS"). */ m = (int) (sizeof(a[0])/sizeof(a[0][0])); /* Does not work here because the "decay" in "pointer decay" is meant literally--information is lost. */ printf("FUN1: %zu\n",sizeof(a)/sizeof(a[0])); for (i = 0; i < n; i ) { for (j = 0; j < m; j ) { printf("array[%d][%d]=%d\n", i, j, a[i][j]); } } }

2 数组指针做函数返回值

数组指针做函数返回值时，数组指针是指指针目标类型为数组元素的指针。

#include <stdio.h> #include <malloc.h> char(*weekday())[5] { char(*wee)[5] = (char(*)[5])malloc(sizeof(char)*5*7); char* str[] = {"Mon.","Tue","Wed.","Thu.","Fri.","Sat.","Sun."}; for(int i=0;i<7;i ) for(int j=0;j<5;j ) wee[i][j] = str[i][j]; return wee; } int main() { char(*week)[5] = weekday(); for(int i=0;i<7;i ) printf("%s\n",week[i]); free(week); setbuf(stdin,NULL); getchar(); }

3 函数指针做函数参数

函数指针做函数参数，可以封装函数体中因因应不同需求而需“变化”的代码，避免“硬”编程，让代码更加通用和泛化。

#include <stdio.h> void sort(int arr[],int size,bool(*comp)(int,int)) { for(int i=0;i<size-1;i ) for(int j=0;j<size-i-1;j ) if(comp(arr[j],arr[j 1])) { int t = arr[j 1]; arr[j 1] = arr[j]; arr[j]=t; } } bool Comp(int a,int b) { return a<b; } int main(void) { int arr[]={2,1,4,5,3,9,6,8,7}; int n = sizeof arr / sizeof *arr; sort(arr,n,Comp); for(int i=0;i<n;i ) printf("%d ",arr[i]); getchar(); return 0; }

4 函数指针做函数返回值

用函数返回函数指针，可以让同类函数具有相同的接口。

#include <stdio.h> enum Op { ADD = ' ', SUB = '-', }; int add(int a, int b) { return a b; } int sub(int a, int b) { return a - b; } /* getmath: return the appropriate math function */ int (*getmath(enum Op op))(int,int) { switch (op) { case ADD: return &add; case SUB: return ⊂ default: return NULL; } } int main(void) { int a, b, c; int (*fp)(int,int); fp = getmath(ADD); a = 1, b = 2; c = (*fp)(a, b); printf("%d %d = %d\n", a, b, c); getchar(); return 0; }

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