Page 103 - C-Language

you should always check the return value for easier debugging.

This is bad:

char* x = malloc(100000000000UL * sizeof *x);
/* more code */
scanf("%s", x); /* This might invoke undefined behaviour and if lucky causes a segmentation
violation, unless your system has a lot of memory */

This is good:

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

int main(void)
{
char* x = malloc(100000000000UL * sizeof *x);
if (x == NULL) {
perror("malloc() failed");
exit(EXIT_FAILURE);
}

if (scanf("%s", x) != 1) {
fprintf(stderr, "could not read string\n");
free(x);
exit(EXIT_FAILURE);
}

/* Do stuff with x. */

/* Clean up. */
free(x);

return EXIT_SUCCESS;
}

This way you know right away the cause of error, otherwise you might spend hours looking for a
bug in a completely wrong place.

Newline character is not consumed in typical scanf() call

When this program

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

int main(void) {
int num = 0;
char str[128], *lf;

scanf("%d", &num);
fgets(str, sizeof(str), stdin);

if ((lf = strchr(str, '\n')) != NULL) *lf = '\0';
printf("%d \"%s\"\n", num, str);
return 0;

https://riptutorial.com/ 79