How to assign file data to structure variables in C language-Computer Knowledge-php.cn

How to assign file data to structure variables in C language

/*The sex[2] given does not seem to fit 4 letters. . . . . . But I understand the meaning of the question.

**In order to simplify programming, I changed all the data in the structure into character arrays. If numbers are needed, just add another step of conversion**. It is relatively simple and I won’t write it. In addition, it is used in the program A structure array. If you are not sure how many lines there are in the file, in order to save memory, you can use dynamic allocation. It was written in a hurry, and there is no encapsulated function, but it is indeed usable, so just make do with it~~~

#include <...>

struct employ

{

char id[10];

char name[10];

char sex[5];

char age[5];

char edu[10];

char wage[5];

char address[20];

char number[20];

};

int _tmain(int argc, _TCHAR* argv[])

{

char buf[100];

FILE* pf=NULL;

struct employ Ep[10]={};

int flag=0;

pf=fopen("employ.dat","r");

if(!pf)

{

printf("File opening failed!\n");

system("pause");

return -1;

}

while(fgets(buf,99,pf))

{

char* pchar=buf;

for(int i=0;i

{

Ep[flag].id[i]=*pchar;

if(*pchar ==',')

break;

}

for(int i=0;i

{

Ep[flag].name[i]=*pchar;

if(*pchar ==',')

break;

}

for(int i=0;i

{

Ep[flag].sex[i]=*pchar;

if(*pchar ==',')

break;

}

for(int i=0;i

{

Ep[flag].age[i]=*pchar;

if(*pchar ==',')

break;

}

for(int i=0;i

{

Ep[flag].edu[i]=*pchar;

if(*pchar ==',')

break;

}

for(int i=0;i

{

Ep[flag].wage[i]=*pchar;

if(*pchar ==',')

break;

}

for(int i=0;i

{

Ep[flag].address[i]=*pchar;

if(*pchar ==',')

break;

}

for(int i=0;i

{

Ep[flag].number[i]=*pchar;

if(!*pchar )

break;

}

//printf(＂%s＂,buf);

flag;

}

fclose(pf);

system("pause");

return 0;

}

How to use data variables in txt files in c language

Use fopen and fscanf functions to read content from txt files and perform simple operations.

1.Fopen function prototype: FILE * fopen(const char * path, const char * mode);

The first parameter of the fopen function is the file path, and the second parameter is the opening method. There are the following methods:

r Open the file in read-only mode. The file must exist.

r Open the file in read-write mode. The file must exist.

rb opens a binary file for reading and writing, allowing data to be read.

rw Read and Write Opens a text file, allowing reading and writing.

w Open a write-only file. If the file exists, the file length will be cleared to 0, that is, the file content will disappear. If the file does not exist, create the file.

w Open a readable and writable file. If the file exists, the file length will be cleared to zero, that is, the file content will disappear. If the file does not exist, create the file.

a Open a write-only file in append mode. If the file does not exist, the file will be created. If the file exists, the written data will be added to the end of the file, that is, the original content of the file will be retained. (EOF character reserved)

a Open a read-write file in append mode. If the file does not exist, the file will be created. If the file exists, the written data will be added to the end of the file, that is, the original content of the file will be retained. (The original EOF character is not retained)

wb Open or create a new binary file for writing only; only data writing is allowed.

wb read and write Open or create a binary file, allowing reading and writing.

wt Open or create a text file for reading and writing; reading and writing are allowed.

at opens a text file for reading and writing, allowing reading or appending data to the end of the text.

ab opens a binary file for reading and writing, allowing reading or appending data to the end of the file.

The above-mentioned form strings can be added with a b character, such as rb, w b or ab, etc. The b character is added to tell the function library that the file opened is a binary file, not a plain text file.

Return value: After the file is successfully opened, the file pointer pointing to the stream will be returned. If the file opening fails, NULL is returned and the error code is stored in errno.

2. Routine:

#include

#define F_PATH "d:\\myfile\\file.dat"

charc;

intmain(){

FILE*fp=NULL; //Need to pay attention

fp=fopen(F_PATH,"r");

if(NULL==fp) return-1; //To return an error code

while(fscanf(fp,"%c",&c)!=EOF) printf("%c",c); //Read from the text and print it out on the console

fclose(fp);

fp=NULL; //Needs to point to null, otherwise it will point to the original opened file address

return0;

}

How does C voice read a certain line in a txt file and assign it to a variable

The simplest method is to read line by line, but only get the line of data you want. Below is a simple example I wrote. I drew prizes three times and there were no duplicates.

#include

#define PEOPLE_NUM 10 //There are 10 names in my file

void get_prize(FILE* fp, char prize_name[])

{

int num;

int i;

fseek(fp, 0, SEEK_SET);

printf("start...\n");

num = rand() % PEOPLE_NUM 1;

for(i = 0; i

{

fgets(prize_name, 32, fp);

}

printf("%s get the prize!!!\n", prize_name);

}

int main()

{

FILE* fp = fopen("name.txt", "r");

int prize_num;

int i;

char prize_name[32] = {0};

srand(time(0));

for(i = 0; i

{

printf(＂\n＂);

get_prize(fp, prize_name);

}

fclose(fp);

return 0;

}The file looks like this:

How to assign file data to structure variables in C language

Run screenshot:

How to assign file data to structure variables in C language

When writing this kind of program, the files where you save names must be arranged neatly so that the program can process them easily. good luck.

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