함수를 종료 한 후 realloc을 사용하여 값을 배열에 저장하지 않습니다.

Question

배열의 데이터베이스에 값을 입력하고 함수 내에서 addReader으로 값을 전송하면 값이 성공적으로 저장되지만 다시 main으로 돌아갈 때 입력 된 값은 사라집니다.

주어진 다음 코드

reader* addReader(reader *rdr, int *readNum){  //adding a reader from the user 
    char string[1000]; 
    rdr = (reader*)realloc(rdr,sizeof(reader)*(*readNum+1));// build new struct array (bigger), with the old values 
    checkreader(rdr);// check if can get memory 
    printf("please enter the I.D. of the student you want to add:\n"); 
    scanf("%s",string);// get from operant 
    rdr[*readNum].id=cutToStr(string);// put id in struct 
    printf("please add the reader's first name:\n"); 
    scanf("%s",string);// get from operant 
    rdr[*readNum].first_name=cutToStr(string);// put first name in struct 
    printf("please add the reader's last name:\n"); 
    scanf("%s",string);// get from operant 
    rdr[*readNum].last_name=cutToStr(string);// put last name in struct 
    printf("please add the reader's address:\n"); 
    scanf("%s",string);// get from operant 
    rdr[*readNum].address=cutToStr(string);// put adress in struct 
    printf("please add the reader's phone:\n"); 
    scanf("%s",string);// get from operant 
    rdr[*readNum].phone=cutToStr(string);// put phone in struct 
    rdr[*readNum].numToTake = 5;// change value of numbers to tke to 5 
    *readNum = *readNum + 1;// rise the number of the readers 
    return rdr;// return the new structs array 
} 

함수 호출 메인 주어진 :

rdr=addReader(rdr,readNum); 

Defenition 호출 함수 주어 realloc

reader* readerBuilder(reader *rdr, int *readNum){  //building all the readers 
    FILE *read; 
    int i=1; 
    char *str; 
    read = fopen("Readers.txt","r"); 
    checkFile(read); 
    str = readFromFile(read); 
    while(str != NULL) 
    { 
     rdr[i-1] = *cutToRdr(str); 
     str = readFromFile(read); 
     if(str != NULL){ 
      i++; 
      rdr = (reader*)realloc(rdr,sizeof(reader)*i); 
      checkreader(rdr); 
     } 
    } 
    fclose(read); 
    *readNum = i; 
    return rdr; 
} 

와 동적 배열을 만드는 독자 struct :

typedef struct reader{ 
    int numToTake; 
    char *first_name, *last_name, *address, *phone, *id; 
}reader; 

내가 뭘 잘못하고 있니? 감사합니다, David

EDIT!

여전히 작동하지 않습니다. 코드의 새로운 버전 :

void addReader(reader **rdr, int *readNum){  //adding a reader from the user 
    char string[1000]; 
    rdr = (reader**)realloc(rdr,sizeof(reader*)*(*readNum+1));// build new struct array (bigger), with the old values 
    checkreader(*rdr);// check if can get memory 
    printf("please enter the I.D. of the student you want to add:\n"); 
    scanf("%s",string);// get from operant 
    rdr[*readNum]->id=cutToStr(string);// put id in struct 
    printf("please add the reader's first name:\n"); 
    scanf("%s",string);// get from operant 
    rdr[*readNum]->first_name=cutToStr(string);// put first name in struct 
    printf("please add the reader's last name:\n"); 
    scanf("%s",string);// get from operant 
    rdr[*readNum]->last_name=cutToStr(string);// put last name in struct 
    printf("please add the reader's address:\n"); 
    scanf("%s",string);// get from operant 
    rdr[*readNum]->address=cutToStr(string);// put adress in struct 
    printf("please add the reader's phone:\n"); 
    scanf("%s",string);// get from operant 
    rdr[*readNum]->phone=cutToStr(string);// put phone in struct 
    rdr[*readNum]->numToTake = 5;// change value of numbers to tke to 5 
    *readNum = *readNum + 1;// rise the number of the readers 
    //return rdr;// return the new structs array 

} 주에서

새로운 부름 :

addReader(&rdr,readNum); 

Answer 1

당신은 **rdr을 통과해야합니다

reader* addReader(reader **rdr, int *readNum) 
         ^^ 

또한,이 추가 새로운 간접 레벨 인 realloc.

코드를 사용하면 실제 포인터가 아닌 포인터 사본에 realloc이 있습니다.