字符串函数参数传入传出（字符串反转）

/***
strstr.c
***/
#include<stdio.h>
#include<string.h>

//求字符串p中abcd出现的次数
//自定义函数接口完成业务函数和main函数分开
int getCount(char *mystr,char *sub,int *ncount)
{

    int ret = 0;
    if(mystr == NULL || sub == NULL || ncount == NULL)
    {
    ret = -1;
    printf("one of point is NULL\n");
    return ret;
    }

    int tmpCount = 0;
    char *p = mystr;  //不要轻易改变形参的值

    do
    {
    p = strstr(p,sub);
    if(p != NULL)
    {
        tmpCount++;
        p = p +strlen(sub);
    }
    else
    {
        break;
    }
    }while(*p != '\0');

    *ncount = tmpCount;   //间接赋值是指针存在的最大意义
    return ret;
}


int main()
{
    int ret = 0;
    char *p = "abcd11122abcd3333abcd3456abc";
    int count = 0;
    char sub[] = "abcd";

    ret = getCount(p,sub,&count);
    if(ret != 0)
    {
    printf("getCount error ret:%d\n",ret);
    return ret;
    }

    printf("count:%d\n",count);
    return 0;
}