Re: What's wrong with this code?
LL wrote:
#include <stdio.h>
#include <stdlib.h>
struct Student {
int id;
char* name;
You really should use strings (std::string) instead of raw character arrays.
};
void getStudents(struct Student*, int);
void printStudents(struct Student*, int);
main() {
Your main() function is missing a return type.
int n;
struct Student *s;
printf("Number of students: ");
scanf("%d", &n);
s=(struct Student*)malloc(n*(sizeof(struct Student)));
Prefer operator new over malloc in C++:
s = new Student[n];
Or even better, use std::vector and don't manually allocate dynamic memory
at all. Especially if you're a beginner, that will make things a lot easier.
getStudents(s,n);
printStudents(s,n);
free(s);
delete [] s; // if you use operator new
exit(0);
}
void getStudents(struct Student *s, int n) {
for (int i=0; i<n; i++) {
printf("Student Name: ");
scanf("%s", s->name);
s->name is an uninitialized pointer. So you're writing to whatever random
memory location it currently happens to point to. You need to let it point
to some memory that can take the character data to be read from stdin.
Unfortunately, you don't know how many characters the user is going to
enter. What you can do is allocate some large enough block of memory before
calling scanf and then limit the number of characters that it reads. This
can be done with the format string. Much simpler, and without that limit,
would be to use std::string and std::cin.
printf("Student ID: ");
scanf("%d", &s->id);
s++;
}
}
void printStudents(struct Student *s, int n) {
for(int i=0;i<n;i++) {
printf("Student Name: %s", s->name);
printf("ID: %d", s->id);
s++;
}
}