Thread: is this right way to use malloc.

i would like to ask if this is the right way to use malloc or if i am doing anything wrong.
i just turned the page about structures a few days ago in the book i am using.
thanks for the time to comment.

Code:

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

struct contents
{
	int chars;
	int digits;
	int others;
};
void PrintUsage(const char *progname);
int main(int argc, char** argv)
{
	int c;
	int i;
	int ch,digit,other;
	    ch=digit=other=0;

	FILE *fp;
	
	  if( argc == 1 )
	  {
		   PrintUsage(argv[0]);
		   exit(EXIT_FAILURE);
	  } 
		  
		  struct contents *count=malloc(sizeof(count));
		  
		  if(count == NULL)
		  { 
			 errno=EINVAL;
			 perror(argv[0]);
		        exit(1);
                 }
		  
		 for(i=1;i< argc;i++)
               {
	                if((fp=fopen(argv[i],"r")) == NULL)
	                {
                            errno=EINVAL;
		                    perror(argv[0]);
	                        exit(EXIT_FAILURE);
	                }

	              while((c=fgetc(fp))!= EOF)
	             {
		             switch(c)
		            {
		            	  case '1':case '2':case '3':case '4':case '5':
			              case '6':case '7':case '8':case '9':case '0':
			              digit++;  
				      count->digits++;
			              case ' ': case '\n': case '\t':
			              other++;
				     count->others++;
			              default:
			              ch++;
				     count->chars++;
		            }

             	}  
	/* it prints total of the files if more than 1 file is counted. for now its considered a feature :) */
   fprintf(stdout,"nchar %d ndigit %d nother %d %s\n",ch,digit,other,argv[i]);
   fprintf(stdout,"nchar %d ndigit %d nohter %d %s\n",count->chars,count->digits,count->others,argv[i]);

          } /* end for loop*/
		  
	     fclose(fp);
		free(count);
	     count=NULL;
	
	return 0;
}

void PrintUsage(const char *progname)
{
	fprintf(stdout," usage: %s [file]              \n"
	               "counts chars digits and others \n",progname);
}

thanks.

i completely forgot the break statements. it was just a rather hello world like project i started out last night so i just posted what i got from before i went to bed.

sorry the indent is a bit off. i fine tuned it before posting.

Originally Posted by laserlight

This is not correct:

Code:

struct contents *count=malloc(sizeof(count));

It should be:

Code:

struct contents *count = malloc(sizeof(*count));

However, in this case it would be better not to use malloc at all since you do not need dynamic memory allocation.

By the way, you need to indent more consistently. Perhaps you are mixing tabs and spaces?

i dissagree
it should be
struct contents *count=malloc(sizeof(struct contents));

count is just a variable its not a type

ahhhh aint that the coolest thing