题目：求字符串'abcd'出现的次数
要求：自定义函数接口，完成上述需求；自定义的函数和main函数分开
1、do-while模型
int main08()
{
//strstr(str,str2);
int cout = 0;
//初始化 让p指针达到查找的条件
char *p = "abcd11122abcd3344abcd444abdqq";
do
{
p = strstr(p,"abcd");
if(p != NULL)
{
cout ++;
p = p + strlen("abcd");//指针达到下次查找的条件
}
else
{
break;
}
}while(*p != '\0');
printf("cout:%d \n",cout);
printf("Hello world!\n");
system("pause");
return 0;
}
2、while模型
//while模型
int main09()
{
int cout = 0;
//初始化 让p指针达到查找的条件
char *p = "abcd11122abcd3344abcd444abdqq";
while(p = strstr(p,"abcd"))
{
cout ++;
p = p + strlen("abcd");//指针达到下次查找的条件
if(*p == '\0')
{
break;
}
}
printf("cout:%d \n",cout);
printf("Hello world!\n");
system("pause");
return 0;
}
3、定义函数接口
//函数接口
int getNum(char *mystr,/*in*/char *substr,/*in*/int *ncount)
{
char *p = mystr;
int tmpcount = 0;
int ret = 0;
if(mystr == NULL || substr == NULL || ncount == NULL)
{
ret = -1;
printf("%d:func getNum() error:%d (mystr == NULL || substr == NULL || ncount == NULL)\n",__LINE__,ret);
return ret;
}
do
{
p = strstr(p,substr);
if(p != NULL)
{
tmpcount ++;
p = p + strlen(substr);//指针达到下次查找的条件
}
else
{
break;
}
}while(*p != '\0');
*ncount = tmpcount;//间接赋值是指针存在的最大的意义
return 0;
}
int main()
{
//指针做形参并做输入类型时，需要在主调函数中分配内存
char *p = "abcd11122abcd3344abcd444abdqq";
char sub[] = "abcd";
int count = 0;
int ret = 0;
// ret = getNum(p,sub,&count);
ret = getNum(p,NULL,&count);
if(ret != 0)
{
printf("func getNum error!\n");
return ret;
}
printf("count = %d \n",count);
system("pause");
return 0;
}
