C语言银行管理程序报错：无法将char**转换为char*的求助

Hey there! Let's walk through fixing the error you're facing, plus a few other small issues in your code to get it running smoothly.

1. The Core Error: char** to char* Mismatch #

The error cannot convert 'char**' to 'char*' for argument '1' to 'char* strcpy(char*, const char*)' comes from how you defined the name field in your bank struct:

typedef struct bank {
    char *name[NAME_LEN]; // ❌ This is an array of char pointers (char**)
    // ... rest of the struct
} bank;

When you call strcpy(t->name, name), t->name is the name of an array of pointers, which decays to a char** type. But strcpy expects its first argument to be a char* (a pointer to a character array where it can copy the string).

Fix: Change the name field to a character array instead:

typedef struct bank {
    char name[NAME_LEN]; // ✅ This is a char array (decays to char*)
    int id;
    int money;
    struct bank *next;
} bank;

This way, t->name is a valid char* pointer that strcpy can use.

2. Other Fixes for Syntax & Logic Issues #

Let's address a few other bugs that would cause your program to crash or behave incorrectly:

a. Syntax Error in WithDraw Function #

You missed a comparison operator in the balance check:

// ❌ Original broken line
if (t->money {
// ✅ Fixed version
if (t->money < money) {

b. Linked List Insertion Logic in ReadAccount #

Your insertion order was reversed, which would break the linked list:

// ❌ Original
// t->next = head->next; 
// head->next = t;
// ✅ Fixed order
t->next = head->next; // Point new node to the first existing node
head->next = t;       // Update head to point to the new node

c. File Write Cleanup in WriteAccount #

When using rewind(fp) and writing, old content longer than the new data will remain in the file. Add code to truncate the file before writing to avoid leftover data:

void WriteAccount(FILE *fp) {
    bank *t;
    rewind(fp);
    // Truncate the file to 0 size to remove old content
    ftruncate(fileno(fp), 0); // Add this line (needs #include <unistd.h>)
    for (t = head->next; t != tail; t = t->next) {
        fprintf(fp, "%d %s %d\n", t->id, t->name, t->money);
    }
}

Don't forget to add #include <unistd.h> at the top for ftruncate and fileno.

Fixed Complete Code #

Here's the full corrected code with all the fixes applied:

#define NAME_LEN 20 
#include "stdio.h" 
#include "stdlib.h" 
#include "string.h"
#include <unistd.h> // Added for ftruncate and fileno
#pragma warning(disable:4996) 

typedef struct bank { 
    char name[NAME_LEN]; // Fixed: char array instead of pointer array
    int id; 
    int money; 
    struct bank *next; 
} bank; 

bank *head, *tail; 

void Init_account(FILE *fp); 
void Make_account(FILE *fp); 
void Deposit(FILE *fp); 
void WithDraw(FILE *fp); 
void WriteAccount(FILE *fp); 
void Account_inquire(void); 
void ReadAccount(int id, char *name, int money); 

void Init_account(FILE *fp) { 
    int id; 
    char name[NAME_LEN]; 
    int money; 
    head = (bank *)malloc(sizeof(bank)); 
    tail = (bank *)malloc(sizeof(bank)); 
    head->next = tail; 
    tail->next = tail; 

    while (fscanf(fp, "%d %s %d", &id, name, &money) == 3){ 
        ReadAccount(id, name, money); 
    } 
} 

void ReadAccount(int id, char *name, int money) { 
    bank *t; 
    t = (bank *)malloc(sizeof(bank)); 
    t->id = id; 
    strcpy(t->name, name); 
    t->money = money; 
    // Fixed insertion order
    t->next = head->next; 
    head->next = t; 
} 

void Make_account(FILE *fp) { 
    int id; 
    char name[NAME_LEN]; 
    int money; 
    bank *t; 
    t = (bank *)malloc(sizeof(bank)); 

    printf("\n*********계좌 생성*********\n"); 
    printf("계좌번호 : "); 
    scanf("%d", &id); 
    printf("예 금 주 : "); 
    scanf("%s", name); 
    printf("입 금 액 : "); 
    scanf("%d", &money); 

    t->id = id; 
    strcpy(t->name, name); 
    t->money = money; 
    t->next = head->next; 
    head->next = t; 

    WriteAccount(fp); 
} 

void Deposit(FILE *fp) { 
    int id; 
    int money; 
    bank *t; 

    printf("계좌번호 : "); 
    scanf("%d", &id); 
    printf("입 금 액 : "); 
    scanf("%d", &money); 

    for (t = head->next; t != tail; t = t->next) { 
        if (t->id == id) { 
            t->money += money; 
            WriteAccount(fp); 
            return; 
        } 
    } 
    printf("없는 계좌번호입니다.\n"); 
} 

void WithDraw(FILE *fp) { 
    int id; 
    int money; 
    bank *t; 

    printf("계좌번호 : "); 
    scanf("%d", &id); 
    printf("출 금 액 : "); 
    scanf("%d", &money); 

    for (t = head->next; t != tail; t = t->next) { 
        if (t->id == id) { 
            // Fixed balance check syntax
            if (t->money < money) { 
                printf("출금액이 잔액을 초과할 수 없습니다.\n"); 
                return; 
            } else { 
                t->money -= money; 
            } 
            WriteAccount(fp); 
            return; 
        } 
    } 
    printf("없는 계좌번호입니다.\n"); 
} 

void Account_inquire(void) { 
    bank *t; 
    for (t = head->next; t != tail; t = t->next) { 
        printf("\n*********잔액 조회*********\n"); 
        printf("계좌번호 : %d\n", t->id); 
        printf("예 금 주 : %s님\n", t->name); 
        printf("잔 액 : %d원\n\n", t->money); 
    } 
} 

void WriteAccount(FILE *fp) { 
    bank *t; 
    rewind(fp); 
    // Truncate file to remove old content before writing
    ftruncate(fileno(fp), 0); 
    for (t = head->next; t != tail; t = t->next) { 
        fprintf(fp, "%d %s %d\n", t->id, t->name, t->money); 
    } 
} 

int main() { 
    int input; 
    FILE *fp; 
    fp = fopen("data.txt", "r+"); 

    if (fp == NULL) { 
        // Handle case where file doesn't exist
        fp = fopen("data.txt", "w+"); 
    }

    Init_account(fp); 

    do { 
        printf("계좌 생성&관리 프로그램입니다. 원하시는 번호를 입력하세요.\n"); 
        printf("*********************************************\n"); 
        printf("1)계좌 생성 2)계좌 조회 3)입금 4)출금 5)종료\n"); 
        printf("*********************************************\n"); 
        printf("입력 >"); 
        scanf("%d", &input); 

        switch (input){ 
            case 1: 
                Make_account(fp); 
                break; 
            case 2: 
                Account_inquire(); 
                break; 
            case 3: 
                Deposit(fp); 
                break; 
            case 4: 
                WithDraw(fp); 
                break; 
            case 5: 
                input = 0; 
                free(head); 
                free(tail); 
                break; 
            default: 
                printf("잘못 입력하셨습니다. \n"); 
                break; // Removed recursive main call to avoid stack overflow
        } 
    } while (input != 0); 

    fclose(fp); // Don't forget to close the file!
    return 0; 
}

I also added a few extra improvements:

• File existence check in main() (creates the file if it doesn't exist)
• Closed the file in main() to avoid resource leaks
• Removed the recursive call to main() in the default case (this could cause stack overflow with repeated bad inputs)

内容的提问来源于stack exchange，提问作者Rozwel Gustab