• C

Declare a variable without initialization

Hello,
after declaration of char str[1024]; (without intialization or assignment), what value the str points to? Does char str[1024]; equal to char str[1024]="";? Thanks.
rongzAsked:
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sunnycoderCommented:
Hi rongz,
> what value the str points to?
str refers to the address of first element of the array ... however, the array itself will contain junk ... it is impossible to tell what are its content. Exceptions are global and static variables which are automatically set to 0s

>Does char str[1024]; equal to char str[1024]="";?
No ... As automatic variable, it will have unpredictable contents

Cheers!
Sunny:o)
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rongzAuthor Commented:
However, running the following code, I always get "hit" result. Why?

------------------------------------
#include <string.h>
#include <stdio.h>
void main(int argc, char **argv){
  char max[124];

  if (strcmp(max, "")==0)
    printf("hit\n");
  else
    printf("not hit\n");

}
0
rstaveleyCommented:
Memory has a lot of zeros in it. You got lucky.
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rstaveleyCommented:
This typically works too, but you shouldn't depend on it:
--------8<--------
#include <stdio.h>

void foo();
void foo2();

int main()
{
      foo();
      foo2();
}

void foo()
{
char buf[256];

      strcpy(buf,"Hello, World\n");
}

void foo2()
{
char buf[256];

      printf(buf);
}
--------8<--------
0
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