向c

Question

我想用c编写一个程序，该程序管理具有3个属性的银行账户结构数组： 1 -账户号， 2 -账户余额和 3 -帐户所有者。

我想写一个函数：

• 在用户每次按“ a”时添加新帐户，
• 用户必须输入余额和所有者名称，但必须自动分配帐号，并在创建新帐户时递增。

这是我到目前为止的代码：

#include <stdio.h>

struct bancaccount {
  int num;
  double balance;
  char owner;
};

void maintext(); //prototype of the function that print the main text
void addaccount();

void main(void) {
  struct bankaccount account[50];

  maintext();

  char ch;
  ch = getchar();

  if (ch == 'a') {
    addaccount();
    maintext();
  }

  else if (ch == 'b') {
    printf("Result: show");
  }

  else {
    printf("another key was pressed ");
  }

}

void maintext() {
  printf("tap one of this keys : \n"
         " a : to add a new account \n"
         " b : to see all accounts\n");
}

void addaccount(struct comptebanc num) {
  num++; //this seems not possible it gives an error, what should i do insteed 
  num = num; 
  printf("owner name : ");
  scanf("%s", account.owner);
  print("balance : ");
  scanf("%lf", account.balance);

  printf("\n\n");
  printf("Num : %d\n", account.num);
  printf("Prop : %s\n", account.owner);
  printf("Solde : %lf\n", account.balance);
}

如何为每个新帐户分配一个号码？ 以及如何在结构数组中保存新元素？ 谢谢您的帮助。

我还是一个初学者，所以我确定我在基本面方面犯了一些错误

Answer 1

这是基于您的代码的另一个可行的解决方案。 但是在此示例中，我使用了 scanf_s 函数而不是 scanf 。

#include <stdio.h>

struct bancaccount {
    int num;
    double balance;
    char owner[64];
};

struct bancaccount accounts[10];
int account_id = 0;

void maintext(void)
{
    printf("tap one of this keys : \r\n"
        " a : to add a new account \r\n"
        " b : to see all accounts\r\n");
}

void add_account(void)
{
    accounts[account_id].num = account_id + 1;
    printf("owner name : ");
    scanf_s("%63s", &accounts[account_id].owner, 64);
    printf("balance : ");
    scanf_s("%lf", &accounts[account_id].balance);

    printf("\r\n\r\n");
    printf("Num : %d\r\n", accounts[account_id].num);
    printf("Prop : %s\r\n", accounts[account_id].owner);
    printf("Solde : %lf\r\n", accounts[account_id].balance);
    account_id++;
}

void print_accounts(void)
{
    int i;

    for (i = 0; i < account_id; i++) {
        printf("Num : %d\r\n", accounts[i].num);
        printf("Prop : %s\r\n", accounts[i].owner);
        printf("Solde : %lf\r\n", accounts[i].balance);
        printf("\r\n");
    }       
}

int main(int argc, char *argv[])
{
    char c;

    maintext();

    while (1) {
        c = getchar();

        switch (c) {
        case 'a':
            add_account();
            getchar(); /* consume '\n' */
            break;
        case 'b':
            print_accounts();
            getchar(); /* consume '\n' */
            break;
        case 'q':
            return 0;
        default:
            printf("another key was pressed\r\n");
        }
    }

    return 0;
}

Answer 2

这是您想如何解决的问题。

#include <stdio.h>

typedef struct {
  int num;
  double balance;
  char owner[15];
} bankaccount;

int main() {
  int numAllocated = 0; // Number of accounts allocated
  bankaccount accounts[50];

  int ch;
  printf("\"a\": to add new account\n\"b\": to print all accounts\n");

  void addAccount (bankaccount *, int);
  void printAccounts (bankaccount *, int);
  for ( ;; ) {
    ch = getchar();
    if (ch == '\n' ) continue;
    else if (ch == 'a') {
      addAccount(accounts, numAllocated);
      numAllocated++;
    }
    else if (ch == 'b') printAccounts(accounts, numAllocated);
    else break;
    printf("\"a\": to add new account\n\"b\": to print all accounts\n");
 }
}

void addAccount (bankaccount *account, int num) {
  account[num].num = num + 1;
  printf("Owner's name: ");
  scanf("%s", account[num].owner);
  printf("Balance: ");
  scanf("%lf", &account[num].balance);
}

void printAccounts (bankaccount *accounts, int num) {
  if (num > 0) {
    for (int i = 0; i < num; i++) {
      printf("\n%-10s%d\n", "Acc#:", accounts[i].num);
      printf("%-10s%s\n", "Name:", accounts[i].owner);
      printf("%-10s%.2f\n", "Balance:", accounts[i].balance);
    }
  }
  else printf("No account allocated yet\n");
}

我查看了您的代码示例。尽管您可能会通过阅读有关动态内存，指针和可能的链接列表的信息来使结构变好，从而使此问题变得更好。但是这里是开始，希望您可以从这里开始！

Answer 3

动态数组标记相当混乱，因为您只有静态的。

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

typedef struct {
  int num;
  double balance;
  char *owner;
} bancaccount;

size_t Naccounts = 0;
bancaccount *accounts = NULL;

bancaccount addaccount(int num, double ballance, char *owner)
{
    bancaccount *tmp = realloc(accounts, ++Naccounts * sizeof(*tmp));

    if(tmp)
    {
        accounts = tmp;
        tmp[Naccounts - 1].owner = malloc(strlen(owner) + 1);
        if([Naccounts - 1].owner)
        {
            strcpy(tmp[Naccounts - 1].owner, owner);
            tmp[Naccounts - 1].balance = ballance;
            tmp[Naccounts - 1].num = num;
        }
    }
    return tmp;
}