strcmp giving segmentation fault [duplicate]

Question

this is my code giving segmentation fault

#include <stdio.h>
#include <signal.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>

int main(void) {
    char *get;
    scanf("%s", get);
    int k = strcmp("sachin", get);
    printf("%d", k);
}

thanks for any help;

Answer 1

char *get;

The above statement defines get to be a pointer to a character. It can store the address of an object of type char, not a character itself. The problem is with both scanf and strcmp call. You need to define an array of characters to store the input string.

#include <stdio.h>
#include <string.h>

int main(void) {
    // assuming max string length 40
    // +1 for the terminating null byte added by scanf

    char get[40+1];

    // "%40s" means write at most 40 characters
    // into the buffer get and then add the null byte
    // at the end. This is to guard against buffer overrun by
    // scanf in case the input string is too large for get to store

    scanf("%40s", get);
    int k = strcmp("sachin", get);
    printf("%d", k);

    return 0;
}

Answer 2

You need to allocate memory for the pointer get.

Or use a char array:

char   get[MAX_SIZE];
scanf("%s",get);

When you declare a pointer, it is not pointing to any memory address. You have to explicitly allocate memory for that pointer by malloc (c-style) or new (c++ style).

You will also need to manage the clean operation yourself by free / delete respectively.