how to use fread?

[kumudbhat]

i hav used like this

char mstr[50];
file *fp;
char *fname;
printf("enter d file name\n");
scanf("%s",fname);
fp=fopen(fp,"r");
fread(mstr,1,50,fp);
lex-ana(mstr);//passing to constructor
.
.
.

in output its displaying ilke this
enter filename
test.cpp//filename
input string is a+b ------(- indicates garbage value here)
i mean iam getting contents of file as wel as garbage value
pls help me

[weaknessforcats]

This code:

char *fname;
  printf("enter d file name\n");
  scanf("%s",fname);
 

shows fname to be a pointer that you use without ever initializing it. You need to create an array and put the address of the array in the pointer before using the pointer in your scanf.

[johny10151981]

adding with weaknessforcats, its does not read garbage value.
if you request for

fread(mstr,1,50,fp);

then fread function will read 50 or less than 50 characters as available. fread will return the count of read number.

to solve your problem follow either of these:
1. use memset function to reset all the bytes in mstr variable, example: memset(mstr,0,sizeof mstr); remeber sizeof function wont work accordingly for pointer type character array.
or
2. use the return value of fread function to set total read character. example:

int n=fread(mstr, 1, 50, fp);
mstr[n]=0;
 

the problem with both statements are, if it read all 50 characters then then the program will create an error. it will try to access unallocated memory space. so, safe way is define
char mstr[50]; as

char mstr[51];

figure out rest :)