c - Passing NULL to printf %s -

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• what behavior of printing null printf's %s specifier? 4 answers

#include<stdio.h> #include<string.h>  int main() {     char *ptr = null;      printf("%s", ptr);//the output null     //  printf("%s\n", ptr); //addition of **\n** give segmentation fault       return 0; } 

the first printf outputs: (null). why second printf's output is: segmentation fault (core dumped) on adding: \n?

printf("%s", ptr);

here printf expects valid pointer, points null terminated string, can't pass null it. if so, trigger undefined behaviour, , can't reason output of program.

ps. have found answer might have more details thing might interested in. see here. question seems duplicate of one.