如何使用 scanf 将值分配给其数组是动态创建的 Struct 类型变量的成员

Question

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My main problem is how do I take inputs using scanf to the coeff and exp members declared in the array of Terms which is referenced by a Poly variable member named as ptr and this Poly variable is further referenced by a pointer p.

#include <stdio.h>

struct Term
{
    int coeff;
    int exp;
};

struct Poly
{
    int terms;
    struct Terms *ptr;
};

int main(void)
{

    return 0;
}
//creating the array dynamically
struct Term *createPoly()
{
    struct Poly *p;
    p = (struct Poly *)malloc(sizeof(struct Poly));
    printf("Input the number of terms in the polnomial:\n");
    scanf("%d", p->terms);
    p->ptr = (struct Term *)malloc(sizeof(struct Term) * p->terms);

    return p;
}
//inputting the values
void input(struct Poly *p)
{
    for (int i = 0; i < p->terms; i++)
    {
        printf("Input the term %d coefficient and exponent value!", i);
        scanf("%d%d", &(p->(ptr + i).coeff));
    }
} 

Answer 1

There are many issues.

This is the corrected code with explanations in the end of line comments. The comments without ** show improvements which were not actual errors

#include <stdio.h>
#include <stdlib.h>                   // ** you forgot this

struct Term
{
  int coeff;
  int exp;
};

struct Poly
{
  int nbofterms;                      // nbofterms is better than terms
  struct Term* ptr;                   // ** use Term instead of Terms
};

int main(void)
{

  return 0;
}

//creating the array dynamically
struct Poly* createPoly()             // ** you want a struct Poly and not a struct Term
{
  struct Poly* p;
  p = malloc(sizeof(struct Poly));    // (struct Poly*) cast not needed
  printf("Input the number of terms in the polnomial:\n");
  scanf("%d", &p->nbofterms);             // & added
  p->ptr = malloc(sizeof(struct Term) * p->nbofterms);  // cast not needed

  return p;
}

//inputting the values
void input(struct Poly* p)
{
  for (int i = 0; i < p->nbofterms; i++)
  {
    printf("Input the term %d coefficient and exponent value!", i);
    scanf("%d", &p->ptr[i].coeff);    // ** only one %d and expression corrected
  }
}