指针的输入输出模型是指，在主调函数中分配内存（输入模型）还是被调函数分配内存（输出模型）
#include<stdio.h> #include<stdlib.h> #include <string.h> #include <ctype.h> //指针做输出：被调用函数分配内存 //指针做输入：主调函数分配内存 //求文件中两段话的长度 int getMem(char**myp1,int *mylen1,char**myp2,int *mylen2) { char *temp1 = NULL; char *temp2 = NULL; temp1 = (char*)malloc(100); if (temp1 == NULL) { return -1; } strcpy(temp1,"abcdfefg"); *mylen1 = strlen(temp1); *myp1 = temp1; temp2 = (char*)malloc(100); if (temp2 == NULL) { return -1; } strcpy(temp2,"12345678"); *mylen2 = strlen(temp2); *myp2 = temp2; return 0; } int getMem_free(char**myp1) { char *p = NULL; if (myp1 == NULL) { return -1; } p = *myp1; free(p); *myp1 = NULL; return 0; } int main() { char*p1 = NULL; int len1 = 0; char*p2 = NULL; int len2 = 0; int ret = 0; ret = getMem(&p1,&len1,&p2,&len2); printf("p1:%s\n",p1); printf("p2:%s\n",p2); getMem_free(&p1); getMem_free(&p2); system("pause"); return 0; }