C语言中传递给函数的结构数组

Question

我正在尝试创建一个小程序，该文件从分隔的文件（由“|”）接收输入 例如，文件中的一行如下所示：

name|phone|address|city|state|zip

出于某种原因，每次我试图让它将结构数组中的所有内容写入二进制文件时，数组的链接出错了。我一直在看这个几个小时，无法弄清楚为什么会这样做。我注意到的一个问题是，如果我决定运行该程序并且在向索引1写入内容之后打印出数组的索引0中的内容，则会使索引0混乱（每个索引都包含一个结构）。我不知道为什么。

请帮忙，我一直在键盘上敲打几个小时试图找出它为什么会给我这个问题。对不起，忘了提到它应该运行第一个参数是文件ex的路径 ./ExerciseOne.out /path/to/file.txt

#include <stdio.h>
#include <string.h>
#include <stdlib.h>


/*
 * ExerciseOne.c
 *
 *  Created on: Sep 24, 2012
 *      Author: kevin
 */

typedef struct personal_Info {
    char *Name;
    char *Phone;
    char *address;
    char *city;
    char *state;
    int zip;

} PInfo ;

void loopTokens(PInfo *, char *);
void PrintStruct(PInfo *);
void PrintStructArray(PInfo p[], int);
void transferText(PInfo *, int);
void transferTextBin(PInfo p[], int);
void readTextBin(FILE *, PInfo *, int );

int main(int argc, char *argv[]){
    int index = 0;
    int numLines = 0;
    char *lineOfText = malloc(80);
    //Open File
    FILE *fp;
    if ((fp = fopen(argv[1], "r")) == NULL){
    printf("File could not be opened");
    }
    else {
        fclose(fp);
    fp = fopen(argv[1], "r");//inputs the argv as the vile to read
    }
    fscanf(fp, "%d \n", &numLines);


    //Create Arrays for Binary and Text structs
    PInfo TextInfo[numLines];
    PInfo *TextInfo_ptr;



/*Commented code
 * TextInfo[index] = *TextInfo_ptr;//Point to structure ##Unneeded##
 *  printf("this is before the transferTextBin %s \n", TextInfo[0].Phone);//Works
 */
    while(!feof(fp)&&index<numLines){
      TextInfo_ptr = &TextInfo[index];//Structure points to the proper hole in array; current index//Looks like it advances the count for the ptr
      fgets(lineOfText, 80, fp);
      loopTokens(TextInfo_ptr,  lineOfText);//puts pointer to the array index into function
      printf("this is before the transferTextBin %s \n", TextInfo_ptr->Phone);//Works
      printf("this is before the transferTextBin %s \n", TextInfo[0].Phone);//problem second time around
      printf("this is before the transferTextBin %s \n", TextInfo[1].Phone);//works
      //PrintStruct(TextInfo_ptr);
      index++;
    }


    //transferText(TextInfo, numLines);//Will do it in regular

    printf("this is before the transferTextBin %s \n", TextInfo[0].Phone);//Here it is suddenly losing it
    transferTextBin(TextInfo, numLines);//will do it in bin

    fclose(fp);
    FILE *fBIN;
    fBIN = fopen("fOUT.dat", "rb");// may need to insert this into method
    //readTextBin(fBIN, BinInfo, numLines);
    return(0);
}


void loopTokens(PInfo *p, char *textLine){//Want to pass in INDIVDUAL structs
    char *buffer;
    int index = 0;

  p->Name = malloc(80);
  p->Phone = malloc(80);
  p->address = malloc(80);
  p->city = malloc(80);
  p->state = malloc(80);
  p->zip = 0;

        /* mallocate each field in the current structure */

    buffer = strtok(textLine, "|"); /* Tokenize the string */

    while(buffer != NULL && strcmp(textLine,"\n")){ /* loop through all tokens */
            if(index == 0){
            //strcpy(p->Name,textLine);
            p->Name = buffer;
            buffer = strtok(NULL, "|");
            index++;
            }
            else if(index == 1){
            p->Phone = buffer;
            buffer = strtok(NULL, "|");
            index++;
            }
            else if(index == 2){
            p->address = buffer;
            buffer = strtok(NULL, "|");
            index++;
            }
            else if(index == 3){
            p->city = buffer;
            buffer = strtok(NULL, "|");
            index++;
            }
            else if(index == 4){
            p->state = buffer;
            buffer = strtok(NULL, "|");
            index++;
            }
            else if(index == 5){
                p->zip = 0;
            p->zip = (int)atoi(buffer);
            buffer = strtok(NULL, "|");
            index++;
            }
  }
  index = 0;

}

    void PrintStruct(PInfo *p){//Gets pointer to the struct
        printf("This is the supposed name: %s The Phone is : %s, the address is : %s %s %s %d\n", p->Name, p->Phone, p->address, p->city, p->state, p->zip );
    }
    void PrintStructArray(PInfo p[], int lines){//Gets Entire array of structs; prints everything out
  int index = 0;
    while(index < lines){
      printf("This is the supposed name: %s The Phone is : %s, the address is : %s %s %s %d\n", p[index].Name, p[index].Phone, p[index].address, p[index].city, p[index].state, p[index].zip );
    }
  }
void transferText(PInfo *p, int numLines){//Transfers text
  FILE *fOUT;//open file for writing
  int index = 0;
        fOUT = fopen("fOUT.txt", "w");//Open file for writing

        while(index < numLines){
          fputs(p->Name,fOUT);
          fputs(p->Phone,fOUT);
          fputs(p->address,fOUT);
          fputs(p->city,fOUT);
          fputs(p->state,fOUT);
          fputs(p->zip,fOUT);
        }

        fclose(fOUT);

    }
void transferTextBin(PInfo p[], int numLines){
    FILE *fOUT;//open file for writing
    //int index = 0;
    fOUT = fopen("fOUT.dat", "wb");
    printf("this is the phone of the first index %s", p[0].Phone );
    //printf("Ti the supposed name: %s The Phone is : %s, the address is : %s %s %s %d\n", p[index].Name, p[index].Phone, p[index].address, p[index].city, p[index].state, p[index].zip );
    //while(index < numLines){
/*  fwrite(p[index]->Name, sizeof(p[index]->Name), 1, fOUT);
    fwrite(p[index]->Phone, sizeof(p[index]->Phone), 1, fOUT);
    fwrite(p[index]->address, sizeof(p[index]->address), 1, fOUT);
    fwrite(p[index]->city, sizeof(p[index]->city), 1, fOUT);
    fwrite(p[index]->state, sizeof(p[index]->state), 1, fOUT);*/
    //fwrite(p->zip, sizeof(p->zip), 1, fOUT);
//  }
    fclose(fOUT);
    }







void readTextBin(FILE *fIN, PInfo *bInfo, int numLines){
    int index = 0;
    //char *buffer;
    printf("This is what is in the File: ");
    //bInfo[index].Name = fread(buffer, 80, 1, fIN);
    //bInfo[0]->Name = malloc(80);
    while(!feof(fIN) && index<numLines){
        fread(bInfo[index].Name, 80, 1, fIN);
        fread(bInfo[index].Phone, 80, 1, fIN);
        fread(bInfo[index].address, 80, 1, fIN);
        fread(bInfo[index].city, 80, 1, fIN);
        fread(bInfo[index].state, 80, 1, fIN);
        //fread(bInfo[index]->zip, 80, 1, fIN);
        PrintStruct(bInfo);
        index++;
    }
}

Answer 1

在loopTokens中，您应该strcpy从textLine缓冲区到char*成员的值malloc。您void loopTokens(PInfo *p, char *textLine){ char *buffer; int index = 0; p->Name = malloc(80); /* snip */ buffer = strtok(textLine, "|"); /* Tokenize the string */ while(buffer != NULL && strcmp(textLine,"\n")){ /* loop through all tokens */ if(index == 0){ //strcpy(p->Name,textLine); p->Name = buffer; buffer = strtok(NULL, "|"); index++; } 内存的名称，地址等，

p->Name = buffer;

但是当你指定例如malloc，您丢失了对p->Name内存（错误）的引用，并让char指向textLine指向的数组中的strtok。 NULL修改调用它的缓冲区，并将（p->Name或）指针返回到该缓冲区。

所以textLine和朋友都指向p->Name = buffer;缓冲区，当你在下一行读到时，其内容会发生变化。

而不是strcpy(p->Name, buffer); ，你应该

p->Name

（你已经分配给textLine而不是malloc的内存，所以如果你检查NULL是否返回{{1}}，就没有写在分配内存之外的危险）。

Answer 2

void loopTokens(PInfo *p, char *textLine){
    char *tok;
    int index = 0;

    if(!strcmp(textLine,"\n")) return; /* loop-invariant moved out of the loop */

    for(tok= strtok(textLine, "|"); tok; tok = strtok(NULL, "|") ) {
        switch(index++) {
          case 0:
          p->Name = strdup(tok);
            break;
        case 1:
            p->Phone = strdup(tok);
            break;
        case 2:
            p->address = strdup(tok);
            break;
        case 3:
            p->city = strdup(tok);
            break;
        case 4:
            p->state = strdup(tok);
            break;
        case 5:
            p->zip = 0;
            p->zip = atoi(tok);
            break;
        default:
            return;
            }
     }

}