types and string conversion

[mrkrinkle]

Hi I need to convert numbers to a string using sprintf() and convert a string to numbers using sscanf().

This is the code I have so far and I am not sure how to do the conversion back to a string once they've been converted to floats.

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

void main(){

float x,y,z;
FILE *fp=fopen("temp", "a+");
char *str[20], buf[20];


printf("enter 3 numbers.");
fgets(str, 20, fp);

sscanf(str,"%f,%f,%f", &x,&y,&z);

Any help would be appreciated.

[MK27]

Guess what?

sprintf(str2,"%f,%f,%f", x,y,z);

[sganesh]

I think you have solved your requirement I don't know where are you confusing?
But only one mistake I found that is why are you selecting array of pointers for storage.

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

int main(){

float x,y,z;
FILE *fp=fopen("temp", "a+");
char str[20], buf[20];


printf("enter 3 numbers.");
fgets(str, 20, fp);

sscanf(str,"%f,%f,%f", &x,&y,&z); // string to float conversion

printf("%f %f %f\n",x,y,z);
sprintf(buf,"%f,%f,%f",x,y,z); // float to string conversion

printf("buf:%s\n",buf);

return 0;
}

[vivekraj]

Ganesh program works good.But,I want to add one exception handling in it.

In his program,he opened the file in append mode.If the file not exits,then it will create and it will seek for string from the file.Empty string will be returned.sscanf function will seek for float values in the string.There is no string at all.Then,it will give some garbage value.To avoid this,you change ganesh code into the following.

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

int main(){

float x,y,z;
FILE *fp=fopen("temp", "r+");
if(fp==NULL)
{
        printf ( "No File Found.Create It and Run the Program.\n"  );
        perror("File");
        exit(1);
}
char str[20], buf[20];


printf("Enter 3 numbers:");
fgets(str, 20, fp);
printf ( "STRING:%s\n",str  );

sscanf(str,"%f,%f,%f", &x,&y,&z); // string to float conversion

printf("%f %f %f\n",x,y,z);
sprintf(buf,"%f,%f,%f",x,y,z); // float to string conversion

printf("buf:%s\n",buf);

return 0;
}

[Alexander jack]

code is nice use perror to print the error message
for ex :

 if(fp==NULL)
        {
                        perror(err);
                        exit(1) ;
        }