names3.c

c primer plus 第五版 的源代码

// names3.c -- use pointers and malloc()
#include <stdio.h>
#include <string.h>   // for strcpy(), strlen()
#include <stdlib.h>   // for malloc(), free()

struct namect {
    char * fname;  // using pointers
    char * lname;
    int letters;
};

void getinfo(struct namect *);        // allocates memory
void makeinfo(struct namect *);
void showinfo(const struct namect *);
void cleanup(struct namect *);        // free memory when done

int main(void)
{
    struct namect person;

    getinfo(&person);
    makeinfo(&person);
    showinfo(&person);
    cleanup(&person);
    
    return 0;
}

void getinfo (struct namect * pst)
{
    char temp[81];
    printf("Please enter your first name.\n");
    gets(temp);
    // allocate memory to hold name
    pst->fname = (char *) malloc(strlen(temp) + 1);
    // copy name to allocated memory
    strcpy(pst->fname, temp);
    printf("Please enter your last name.\n");
    gets(temp);
    pst->lname = (char *) malloc(strlen(temp) + 1);
    strcpy(pst->lname, temp);
}

void makeinfo (struct namect * pst)
{
    pst->letters = strlen(pst->fname) +
                   strlen(pst->lname);
}

void showinfo (const struct namect * pst)
{
    printf("%s %s, your name contains %d letters.\n",
        pst->fname, pst->lname, pst->letters);
}

void cleanup(struct namect * pst)
{
    free(pst->fname);
    free(pst->lname);
}