files+structs problem in the printing...

[nullifyed]

I' ll be glad if anyone could help...my problem is the following :

Question_1:
when i run the program i press 1 see some stats, then i press 2 so, i typed name, email and telephone.
after that i typed again 1 and doesn' t respond. So in the 2nd if i closed and opened the infile...i am not sure if it is ok, but i runs as i wish...is it correct?

Question_2:
having the r+ mod in the fclose fuction allows you to read and write and NOT append. Append means write something in the end of the file, whereas write erases everything into the file.txt and writes again in the begining. In this program everything into the file.txt does not erase...why?

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
struct Details{
	char l_name[81];
	char f_name[81];
	char email[81];
	int tel;
};

int main(void){
	FILE *infile;
	struct Details det;
	int cont_num, cont_stats, ch;
	
		infile=fopen("lala.txt","r+");
		if(infile==NULL){
			printf("file didn' t found.\n");
			exit(1);
		}
			printf("file found.\n");

		fscanf(infile,"%d %d", &cont_num, &cont_stats);
		printf("There are %d contacts.\n", cont_num);
		printf("There are %d statistics in every contact.\n", cont_stats);

		printf("To just see the contacts type '1'.\n");
		printf("To apend them type '2',\n");
		printf("To exit type '0'.\n");
		scanf("%d", &ch);
		do{
			if(ch==1){
				while(fscanf(infile,"%s %s %s %d", det.f_name, det.l_name, det.email, &det.tel)!=EOF){
					printf("first name: %s\tlast name: %s\te-mail: %s\ttelephone: %d\t\n", det.f_name, det.l_name, det.email, det.tel);
				}
			}else if(ch==2){
					printf("Type your first name:\n");
						scanf("%s", det.f_name);
					printf("Type your last name:\n");
						scanf("%s", det.l_name);
					printf("Type your e-mail:\n");
						scanf("%s", det.email);
					printf("Type your telephone:\n");
						scanf("%d", &det.tel);
					fprintf(infile,"%s %s %s %d", det.f_name, det.l_name, det.email, det.tel);

					fclose(infile); // close the file and ->
					infile=fopen("lala.txt","r+"); // open again the file....
			}else{
				printf("\nThank you for choosing my program.\n\n");
				exit(0);
			}
			
		printf("To just see the contacts type '1'.\n");
		printf("To apend them type '2',\n");
		printf("To exit type '0'.\n");
		scanf("%d", &ch);		
		}while(ch!=0); 
		
	return 0;
}

[claudiu]

1) Check what happens during your last scanf in the do while loop. What is actually being read in ch?

2) I think you want a+ not r+. Check out the differences:
fopen - C++ Reference

[nullifyed]

2) I think you want a+ not r+. Check out the differences:
fopen - C++ Reference

you are correct....it needs a+, for read and apend.

Everytime it says "write" in the page, it means: delete everything in the file and add the things you type?

[claudiu]

you are correct....it needs a+, for read and apend.

Everytime it says "write" in the page, it means: delete everything in the file and add the things you type?

Yes, read what it says under "w". It explains what it means by "writing" in the rest of the file.

[nullifyed]

"Create an empty file for writing. If a file with the same name already exists its content is erased and the file is treated as a new empty file. "
this is what it says. But my file already exists and it adds in the file what i type....whats wrong?

[Bayint Naung]

I guess whenever option 1 is selected, you want to print everything from the file and for option 2, append to file?
You don't need to close and re-open. Take a look at rewind() function.

[nullifyed]

I guess whenever option 1 is selected, you want to print everything from the file and for option 2, append to file?
You don't need to close and re-open. Take a look at rewind() function.

I did a small research and it is just rewind(FILE *fp);...
but in my case the problem is that i have the mode r+ and reads+apends....does not reads+writes as it should!!

[quzah]

Why haven't you figured out how to use a search engine yet?


Quzah.