Thread: c codes need help,thanks

Originally Posted by matsp

The [optional other stuff] was meant to say that you may have other options you want to pass to gcc - e.g. "-O3" to give you the highest level of optimization, or "-ansi" to ensure that your code is ANSI-C - there are literally hundreds of different options that gcc can be given. A text-file is not one of those. The information that your code needs to open "myfile.txt" is already in the source code.

It also says:
10-2.c:10: warning: empty body in an if-statement

What do you think that means?

--
Mats

thanks for you explanation, i have to learn much more things to know that.

i don't know what that warning means, does is mean the if-statement is not correct or in vain?

the c textbook has that statement exactly.

Originally Posted by Sebastiani

>> i don't know what that warning means, does is mean the if-statement is not correct or in vain?

In vain, I believe.

>> the c textbook has that statement exactly.

Nonetheless, you should know what effect a semicolen has there.

Originally Posted by matsp

Really?!?! Are you sure it has the semicolon before the brace?

--
Mats

Code:

#include <stdio.h>
#include <stdlib.h>
int main(void)
{
	FILE *fp,*fw;// declaring file pointers.
	double val;
	char ch;
	int new;        // new for integer part.
	if((fp = fopen("myfile.txt","r"))==NULL)
	{
	printf("sorry,cannot open the file\n");
	exit(0);
	}
    fw = fopen("mynewfile.txt","w");
	do{
		fscanf(fp, "%lf", &val); //read real number from the file.
		ch = getc(fp);           //get the following number after the realnumber.
		new=val;                 //pass numbers to integer form.cos new is defined intefer
		fprintf(fw,"%d",new);
		printf("%lf",val);    //print out the real number.
		printf("%d",new);      //print out the integer number.
		
		if ( ch=='\n' || ch==EOF )//determin to end the progress if there is a '\n' char or End Of File.
			printf("\n");  // switch to next line.
	}while ( ch != EOF );
	fclose(fp);
	return 0;
}

here is the exact codes, anything wrong? i cannot find it...

Originally Posted by vart

Code:

#include <stdio.h>
#include <stdlib.h>
int main(void)
{
	FILE *fp,*fw;// declaring file pointers.
	double val;
	char ch;
	int new;        // new for integer part.
	if((fp = fopen("myfile.txt","r"))==NULL)
	{
	printf("sorry,cannot open the file\n");
	exit(0);
	}
    fw = fopen("mynewfile.txt","w"); /* not checking return value */
	do{
		fscanf(fp, "%lf", &val); /* not checking return value */
		ch = getc(fp);           /* ch should be int */
		new=val;                 //pass numbers to integer form.cos new is defined intefer
		fprintf(fw,"%d",new); /* don't you need space between numbers? */
		printf("%lf",val);    //print out the real number.
		printf("%d",new);      //print out the integer number.
		
		if ( ch=='\n' || ch==EOF )/* ch should be int to correctly compare with EOF */
			printf("\n");  // switch to next line.
	}while ( ch != EOF );
	fclose(fp); /* what about closing the over file as well ? */
	return 0;
}

Code:

#include <stdio.h>
#include <stdlib.h>
int main(void)
{
	FILE *fp,*fw;// declaring file pointers.
	double val;
	int ch;
	int new;        // new for integer part.
	int i=0;
	if((fp = fopen("a.txt","r"))==NULL)
	{
	printf("sorry,cannot open the file\n");
	exit(0);
	}
    if((fw = fopen("mynewfile.txt","w"))==NULL)
	do{
		fscanf(fp, "%lf", &val); //read real number from the file. i dont know how the check the return number
		ch = getc(fp);           //get the following number after the realnumber.
		new=val;                 //pass numbers to integer form.cos new is defined intefer
		fprintf(fw,"%d",new);// the numbers are arranged in conclum 3*5, with a space to separate them. 
		printf("%lf",val);    //print out the real number.
		printf("%d",new);      //print out the integer number.
		i++;
		
		if ( i%5==0 || ch==EOF )//determin to end the progress if there is a '\n' char or End Of File.
			fprintf(fw,"\n");  // switch to next line.
	}while ( ch != EOF );
	fclose(fp);// what the matter?i just want to close the file
	return 0;
}