程序代码：

void reverse_string(char* string)
{
    char* p_begin=string;
    while(*string!=NULL)
    {
        *string++;
    }
    *string--;
    char* p_end=string;
    char tmp;
    while(*p_begin!=*p_end)
    {
        tmp=*p_begin;
        *p_begin=*p_end;
        *p_end=tmp;
        *p_begin++;
        *p_end--;
    }
}

程序代码：

#include <stdio.h>

void reverse_string(char* string)
{
    char* p_begin=string;
    while(*string!=NULL)
    {
        string++;
    }
    string--;
    char* p_end=string;
    char tmp;
    while(*p_begin!=*p_end)
    {
        tmp=*p_begin;
        *p_begin=*p_end;
        *p_end=tmp;
        p_begin++;
        p_end--;
    }
}


int main()
{
    char test[]="ABC";
    reverse_string(test);
    printf("%s",test);
    return 0;
} 

程序代码：

#include <stdio.h>
#include <string.h>
#include <malloc.h>
int StringLenth(char *chars)
{
    return _msize(chars) / sizeof(char);
}
int main()
{
    int lenth;
    char *a = (char*)malloc(7);
    lenth = StringLenth(a);
    printf("%d\n", lenth);

    strcpy(a, "abc");
    lenth = StringLenth(a);
    printf("%d\n", lenth);
    return 0;
}