Dynamic allocation for text input

[Hengist]

I'm trying to accept arbitrary length strings from stdin. I know that you can't do that automatically in C, so I ask the user to input the size of each string, allocate the memory for it, and then read the string.

#include <stdio.h>
#include <stdlib.h>
 
int main(void)
{
    char *source_string = NULL;
    char *search_string = NULL;
    int source_length = 0, search_length = 0;
 
    puts("How long is your source string?");
    scanf("%d", &source_length);
    source_string = (char *)malloc(source_length + 1);
    puts("Please enter your source string.");
    scanf("%s", &source_string);
 
    puts("How long is your search string?");
    scanf("%d", &search_length);
    search_string = (char *)malloc(search_length + 1);
    puts("Please enter your search string.");
    scanf("%s", &search_string);
 
    printf("Now searching string \"%s\" for characters \"%s\".\n", &source_string, &search_string);
 
    puts("Cleaning up memory...");
    free(source_string);
    free(search_string);
 
    return EXIT_SUCCESS;
}
 

Unfortunately, it doesn't work properly. I've included a sample run below.

How long is your source string?
3
Please enter your source string.
123
How long is your search string?
6
Please enter your search string.
123456
Now searching string "56" for characters "123456".
Segmentation fault

Thanks in advance for any help!

[gpraghuram]

Check this.
I have corrected few issues in the code

#include <stdio.h>
#include <stdlib.h>
 
int main(void)
{
    char *source_string = NULL;
    char *search_string = NULL;
    int source_length = 0, search_length = 0;
 
    puts("How long is your source string?");
    scanf("%d", &source_length);
    source_string = (char *)malloc(source_length + 1);
    puts("Please enter your source string.");
    scanf("%s", source_string);
 
    puts("How long is your search string?");
    scanf("%d", &search_length);
    search_string = (char *)malloc(search_length + 1);
    puts("Please enter your search string.");
    scanf("%s", search_string);
 
    //printf("Now searching string \"%s\" for characters \"%s\".\n", &source_string, &search_string);
    printf("Now searching string \"%s\" for characters \"%s\".\n", source_string, search_string);
 
    puts("Cleaning up memory...");
    free(source_string);
    free(search_string);
 
    return EXIT_SUCCESS;
}
 

Raghuram

[Hengist]

I can't believe I missed that. <shakes head>
It works perfectly now. Thank you for your help!