Unable to store string input into a char pointer

Asked Jul 20 '19 at 10:08

Active Jul 20 '19 at 10:25

Viewed 70 times

I've just started learning how to code in C for uni. I'm trying to take a step up from char arrays and trying to store strings in char pointers, but for some reason the terminal is giving me a weird error.

I'm using CLion and the Ubuntu Terminal. When I run the command make main, it creates a make in the directory, but returns a warning:

main.c:6:19: warning: format ‘%s’ expects a matching ‘char *’ argument 
[-Wformat=]
scanf("%[^\n]%s", s);
             ~^

Here is my code:

#include<stdio.h>

int main(void)
{
    char *s;
    scanf("%[^\n]%s", s);
    printf("Hello World! %s\n", s);
}

And then when I run ./main, the program outputs: Hello World! (null). I'm literally passing a char* into scanf so I don't really know what is causing this error. As a matter of fact, when I tried replacing %s with %*c, make tells me that *c expects an int! I'm honestly pretty confused about his whole thing, so any help would be quite appreciated.

asked Jul 20 '19 at 10:08

dkapur17

@user3121023, that makes sense! So is there a way to fix this code, or would I have to change the pointer to an array? – dkapur17 Jul 20 '19 at 10:15
Try to remove the 2nd percent sign. – user5329483 Jul 20 '19 at 10:16
See [this question](https://stackoverflow.com/questions/37921081/scanf-a-string-in-a-char-pointer) – Moritz Schmidt Jul 20 '19 at 10:16
Does `scanf("%[^\n]", AllocatedBuffer);` work? – user5329483 Jul 20 '19 at 10:18
1

`char s[100]; if (scanf ("%99[^\n]", s) == 1) printf ("Hello World! %s\n", s);` – David C. Rankin Jul 20 '19 at 10:54
Related to https://stackoverflow.com/q/37549594/694576 if not a duplicate to it. – alk Jul 20 '19 at 10:55

Unable to store string input into a char pointer

0 Answers0