指针数组与指向指针的指针

指针数组与指向指针的指针

http://wlkc.gdqy.edu.cn/jpkc/portal/blob?key=173314

指针数组和数组指针的区别

http://allew.blog.163.com/blog/static/3374389720094148449239/

指针数组[组图]

http://school.cnd8.com/c/jiaocheng/9212.htm

函数指针和指针函数

http://lionwq.spaces.eepw.com.cn/articles/article/item/18258

========================================

source 1

#include <stdio.h>
int main(void)
{
    char *ptr[4] = {"beijing", "shanghai", "tianjin", "chongqing"};
    int i, *iptr[3], a[3]={1,2,3},b[3][2]={1,2,3,4,5,6};
    for(i=0; i<4; i++)
        printf("%s/t", ptr[i]);
    printf("/n");
    for(i=0; i<3; i++)
        iptr[i]=&a[i];
    for(i=0; i<3; i++)
        printf("%d/t", *iptr[i]);
    printf("/n");
    for(i=0; i<3; i++)
        iptr[i]=b[i];
    for(i=0; i<3; i++)
        printf("%d:%d/t", *iptr[i], *iptr[i]+1);
    printf("/n");
    return 0;
}

result 1:

[[e-mail] c++]$ gcc -o array_ptr array_ptr.c

[[e-mail] c++]$ ./array_ptr

beijing shanghai tianjin chongqing

1 2 3

1:2 3:4 5:6

========================

source 2

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
void show(char *ptr[], int);
void sort(char *ptr[], int);
int main(void)
{
    char *ptr[4], *tmp;
    int i;
    for(i=0; i<4; i++)
    {
        ptr[i] = (char *)malloc(20);
        fgets(ptr[i], 20, stdin);
    }
    show(ptr, 4);
    
    sort(ptr, 4);
    show(ptr, 4);
    
    return 0;
}
void show(char *ptr[], int num)
{
    int i;
    for(i=0; i<num; i++)
        printf("%10s", ptr[i]);
    
    printf("/n"); //换行
}
void sort(char *ptr[], int num)
{
    int i, j;
    char *tmp;
    
    for(i=0; i<num-1; i++)
        for(j=0; j<num-1-i; j++)
        {
            if(strcmp(ptr[j], ptr[j+1])>0)
            {
                tmp = ptr[j];
                ptr[j]=ptr[j+1];
                ptr[j+1]=tmp;
            }
        }
} 

result 2:

[[e-mail] c++]$ ./array_ptr_sort

beijing

shanghai

tianjin

chongqing

beijing

shanghai

tianjin

chongqing

beijing

chongqing

shanghai

tianjin

=================================

指针函数

Source

#include <stdio.h>
int main()
{
    char *ch(char *, char *);
    char str1[] = "I am glad to meet you";
    char str2[] = "Welcome to study C";
    printf("%s/n", ch(str1, str2));
    return 0;
}
char *ch(char *str1, char *str2)
{
    int i;
    char *p = str2; //指针赋值
    printf("str1: %s/nstr2: %s/n", str1, str2);
    
    return p; //返回指针
}

Result

[[e-mail] c++]$ gcc -o func_pfun func_pfun.c

[[e-mail] c++]$ ./func_pfun

str1: I am glad to meet you

str2: Welcome to study C

Welcome to study C

=================================

函数指针

Source

#include <stdio.h>
int main()
{
    int max(int, int);
    int i, a, b, m;
    int (*f)(); //定义函数指针
    
    scanf("%d %d", &a, &b);
    f = max; //给函数指针f赋值，使它指向函数max
    m = (*f)(a, b); //通过函数指针f调用函数max
    printf("%d %d max: %d/n", a, b, m);
    return 0;
}
int max(int x, int y)
{
    return x>y ? x:y;
}

Result

[e-mail] c++]$ gcc -o func_ptr func_ptr.c

[[e-mail] c++]$ ./func_ptr

3 6

3 6 max: 6