C fprintf() and fscanf()

Writing File : fprintf() function

The fprintf() function is used to write set of characters into file. It sends formatted output to a stream.

Syntax:

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

Example:

    
        #include   
            main(){  
               FILE *fp;  
               fp = fopen("file.txt", "w");//opening file  
               fprintf(fp, "Hello file by fprintf...n");//writing data into file  
               fclose(fp);//closing file  
            }

Reading File : fscanf() function

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

Syntax:

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

Example:

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

Output

Hello file by fprintf...

C File Example: Storing employee information

Let's see a file handling example to store employee information as entered by user from console. We are going to store id, name and salary of the employee.

            
                #include   
                    void main()  
                    {  
                        FILE *fptr;  
                        int id;  
                        char name[30];  
                        float salary;  
                        fptr = fopen("emp.txt", "w+");/*  open for writing */  
                        if (fptr == NULL)  
                        {  
                            printf("File does not exists n");  
                            return;  
                        }  
                        printf("Enter the idn");  
                        scanf("%d", &id);  
                        fprintf(fptr, "Id= %dn", id);  
                        printf("Enter the name n");  
                        scanf("%s", name);  
                        fprintf(fptr, "Name= %sn", name);  
                        printf("Enter the salaryn");  
                        scanf("%f", &salary);  
                        fprintf(fptr, "Salary= %.2fn", salary);  
                        fclose(fptr);  
                    }

Output

Enter the id 1 Enter the name sonoo Enter the salary 120000

Now open file from current directory. For windows operating system, go to TCbin directory, you will see emp.txt file. It will have following information. emp.txt

Output

Id= 1 Name= sonoo Salary= 120000