Modern C for Absolute Beginners: A Friendly Introduction to the C Programming Language

© Slobodan Dmitrović 2021

S. DmitrovićModern C for Absolute Beginnershttps://doi.org/10.1007/978-1-4842-6643-4_37

37. Initialize Variables Before Using Them

Slobodan Dmitrović¹  

(1)

Belgrade, Serbia

 

When we declare local variables, they are not initialized. Their values are undetermined. Trying to access uninitialized variables causes undefined behavior. One use case would be trying to print local, uninitialized variables. The following example demonstrates what should be avoided:

#include <stdio.h>

int main(void)

{

      char c;

      int x;

      double d;

      printf("Accessing uninitialized variables...\n");

      printf("%c, %d, %f\n", c, x, d); // undefined behavior

}

Possible Output:

Accessing uninitialized variables...

[, 32767, 0.000000

In this example, ...