Thread: pointer printing

Why I cannot print the char d in the below code. I get segmentation fault

Code:

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

main(){
char a[]="Cool";
char b[]="things";
	char *c;
	c=a;
	char d;
	d=*(c+2);
	

	printf("%s", c);
	printf("\n %p", c);
	printf("\n %p", ++*c);
	printf("\n %p", *(c+2));
	printf("\n %p", d);
	printf("\n %s", d);
}

this is the problem --> printf("\n %s", d); could you please help me how to print if that is possible?

d is a char. It is not a string, or a pointer, so interpreting it as such is a Bad Thing.

I think you forgot to null terminate your strings cool and things - when you use %s, it tries to print until it find '\0', which is not there, so it runs off the character array and segfaults.

If you want to just print the one character, use %c. If you want to print a string starting at that point, you need to terminate the string somehow.

Or not, that would just be my first guess at a place to begin to debug.

maybe make d an array like this

char d[100];

and to terminate string maybe use d*='/0'
pend a null character to end of string maybe.

im not sure about this though

Originally Posted by KBriggs

I think you forgot to null terminate your strings cool and things - when you use %s, it tries to print until it find '\0', which is not there, so it runs off the character array and segfaults.

If you want to just print the one character, use %c. If you want to print a string starting at that point, you need to terminate the string somehow.

Or not, that would just be my first guess at a place to begin to debug.

The string c is terminated, because a is terminated. The string b is also terminated. It would not be a source of problems if either string were involved. It works because the compiler will compute size requirements when you use the below syntax, and literal strings are always terminated.

char foo[] = "Cool and things";

jeffcobb is right. We need to know what c lady intends - the segfault is happening because she is using a format specifier, %s, with an incompatible value.