CODEWITHSUNDEEP
cbinarybit-manipulationdecimal
user10792793
user10792793

Reputation:

Segmentation Fault when using Bitwise Operators

I'm currently messing around with a project in C that will take in two 8-bit binary numbers and convert them to decimal values. I have a good understanding of the bit-wise operators in C and how they treat numbers, my question is one that revolves around syntax.

ATM my program is very simple:

int main() {
  char *inp1;
  char *inp2;
  unsigned long binNum1;
  unsigned long binNum2;

  printf("Enter the first binary number: "); 
  scanf("%s", inp1); 
  printf("Enter the second binary number: "); 
  scanf("%s", inp2); 

  binNum1 = strtoul(inp1, NULL, 2);
  binNum2 = strtoul(inp1, NULL, 2);

  unsigned long orVal = binNum1 | binNum2;
  unsigned long andVal = binNum1 & binNum2;
  unsigned long exclVal = binNum1 ^ binNum2;

  printf("Your or value is: %lu", orVal);
  printf("Your and value is: %lu", andVal);
  printf("Your exclusive value is: %lu", exclVal);

  return 0;
}

Essentially, I just want to get the value of ORing, ANDing, and EXCLing the two decimal values of each binary number. However, I get a segmentation fault when I run this. I'm pretty sure this is due to syntax, but I can't find much online for this type of problem.

Upvotes: 0

Views: 1013

Answers (1)

Weather Vane
Weather Vane

Reputation: 34585

With these lines

char *inp1;
char *inp2;
...
scanf("%s", inp1);
scanf("%s", inp2);

you have not assigned any memory to inp1 or to inp2. The pointers are uninitialised and this is the probable cause of the segfault.

To simplify it you could do it like this:

char inp1[100];
printf("Enter the first binary number: "); 
if(scanf("%99s", inp1) != 1) {
    return 1;
}

and similarly for inp2.

Upvotes: 5

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