如何在C編程語言的函數中添加記錄（結構體）？

Question

如果作爲參數發送給函數，如何添加記錄？

struct record { 
char name[20]; 
int nr; 
}; 

void AddRecord(struct record **p_allRecs, int p_size); 

int main() { 

struct record *allRecs; 
/* putting in some records manually, size++... */ 
allRecs = (struct record *)malloc(size*sizeof(struct record)); 
} 

AddRecord(&allRecs, size);/* wan't to add a record like this */ 
}/* end main */ 

void AddRecord(struct myRecord **p_allRecs, int p_size){ 
int i; 
struct record *allRecsTemp; /* temporary */ 
allRecsTemp = (struct record *)malloc((p_size+1)*sizeof(struct record));/* oneup */ 
/* first copy existing recs */ 
for(i = 0; i < p_size; i++) { 
strcpy(allRecsTemp[i].name, p_allRecs[i]->name);/* this want't work */ 
allRecsTemp[i].nr = p_allRecs[i]->nr;/* this want't work */ 
} 
/* then ask for new record */ 
printf("Name?"); 
    scanf("%s", &allRecssTemp[p_size].name); 
    printf("Nr? "); 
    scanf("%d", &allRecsTemp[p_size].nr); 
    p_size++; 
    free(p_allRecs); 
    p_allRecs = allRecsTemp; 

Answer 1

在C中，可以指定結構。你可以這樣說：

allRecsTemp[i] = (*p_allRecs)[i]; 

不需要調用strcpy（）等。這樣做應該簡化你的代碼。哦，還有：

free(p_allRecs); 
p_allRecs = allRecsTemp; 

應該是：

free(* p_allRecs); 
* p_allRecs = allRecsTemp; 

記住 - p_allRecs爲s指針的指針，而allRecsTemp只是一個指針。

Answer 2

記住p_allRecs是一個指針的指針記錄數組的開始：

void AddRecord(struct myRecord **p_allRecs, int p_size){ 
    int i; 
    struct record *allRecsTemp; 
    allRecsTemp = (struct record *)malloc((p_size+1)*sizeof(struct record)); 

    memcpy(allRecsTemp, *p_allRecs, p_size*sizeof(struct_record)); // only if records do not contain pointers to one another! 

    free(*p_allRecs); 
    *p_allRecs = allRecsTemp; 

    (*p_allRecs)[p_size].name = "new record name"; 
    (*p_allRecs)[p_size].nr = 3; // or whatever 

}