fprintf() e fscanf() de Arquivo C

Write to file: fprintf() function

The fprintf() function is used to write character sets to a file. It sends formatted output to the stream.

Syntax:

int fprintf(FILE　*stream, const char　*format [, argument, ...])

Example

#include <stdio.h>　
void main(){
　　　FILE　*fp;
　　　fp = fopen("file.txt", "w");//Open file
　　　fprintf(fp, "I am the data written by fprintf...\n");//Write data to file
　　　fclose(fp);//Close file
}

Read file: fscanf() function

The fscanf() function is used to read character sets from a file. It reads a word from the file and returns EOF at the end of the file.

Syntax:

int fscanf(FILE　*stream, const char　*format [, argument, ...])

Example

#include <stdio.h>　
void main(){
　　　FILE　*fp;
　　　char buff[255];//Create a char array to store file data
　　　fp = fopen("file.txt", "r");
　　　while(fscanf(fp, "%s", buff)!=EOF){
　　　printf("%s ", buff );
　　　}
　　　fclose(fp);
}

Saída：

I am the data written by fprintf...

C File Example: Store employee information

Let's see a file processing example that stores employee information entered by the user from the specified console. We will store the employee's ID, name, and salary.

Example

#include <stdio.h>　
void main(){
　　　　FILE　*fptr;
　　　　int id;
　　　　char name[30];
　　　　float salary;
　　　　fptr = fopen("emp.txt", "w+");/*　　Open file in write mode　*/
　　　　if (fptr == NULL)
　　　　{
　　　　　　　　printf("File does not exist\n");
　　　　　　　　return;
　　　　}
　　　　printf("Enter id\n");
　　　　scanf("%d", &id);
　　　　fprintf(fptr, "Id= %d\n", id);
　　　　printf("Enter name\n");
　　　　scanf("%s", name);
　　　　fprintf(fptr, "Name= %s\n", name);
　　　　printf("Enter salary\n");
　　　　scanf("%f", &salary);
　　　　fprintf(fptr, "Salary= %.2f\n", salary);
　　　　fclose(fptr);
}

Saída：

Insira o id　
1
Insira o nome　
sonoo
Insira o salário
120000

Agora abra o arquivo atualmente no diretório. Para o sistema operacional Windows, vá para o diretório do arquivo, onde você verá o arquivo emp.txt. Ele terá as seguintes informações.

emp.txt

Id=　1
Nome=　sonoo
Salário=　120000