c - 堆栈 - 链表实现 - 字符串未正确使用

Question

我使用链表实现在 C 语言中创建了一个堆栈。当我尝试输入字符串时，我遇到了问题。在我推送到堆栈的每个节点中，所有节点中的字符串都等于顶部节点的字符串值。例如：

推>行：9座位字母：A名称： 美国食品药品监督管理局

推>行：3座信：F名称： JFJFJJF

流行<-行：3座信：F名称： JFJFJJF

啪<-行：9座位字母：A名称： JFJFJJF

---

#include <stdio.h>
#include <stdlib.h>
typedef struct {
    int rowNumber;
    char seat;
    char* passengerName;
    struct passengerNode* nextPtr;
} PassengerStack, *PassengerStackPtr;
// prototypes
void top(PassengerStackPtr* topPtr);
void push(PassengerStackPtr* topPtr, int rowNum, char seatLetter, char passengersName[]);
PassengerStackPtr pop(PassengerStackPtr* topPtr);
void printStack(PassengerStackPtr currentPtr);
int full(PassengerStackPtr topPtr);
int empty(PassengerStackPtr topPtr);
int main(void)
{
    PassengerStackPtr passPtr = NULL;
    int choice;
    int rowNumber;
    char seat;
    char passengerName[50];
    printf("Enter choice: n1 to show the first passenger in the stack. n2 to push a passenger in the stack. n3 to "
           "pop off a passenger in the stack. n4 to print the stack. n5 to exit the program.");
    scanf("%d", &choice);
    while(choice != 5) {
    switch(choice) {
    case 1:
        top(passPtr);
        break;
    case 2:
        printf("nEnter a row number: ");
        scanf("%d", &rowNumber);
        printf("nEnter a seat letter: ");
        scanf("%c", &seat);
        scanf("%c", &seat); //skips over if I don't duplicate (don't know why)
        printf("nEnter a name for the passenger: ");
        scanf("%s", &passengerName);
        printf("Entered: n");
        printf("%d", rowNumber);
        printf("n");
        printf("%c", seat);
        printf("n");
        printf("%s", passengerName);
        printf("n");
        push(&passPtr, rowNumber, seat, passengerName);
        break;
    case 3:
        if(!empty(passPtr)) {
        PassengerStackPtr poppedPtr = pop(&passPtr); 
        printf("%d", poppedPtr->rowNumber);
        printf("n");
        printf("%c", poppedPtr->seat);
        printf("n");
        printf("%s", poppedPtr->passengerName);
        printf("n");
        }
        break;
    case 4:
        printStack(passPtr);
        break;
    case 5:
        // add exit here !!!!!!!!!!
        break;
    default:
        printf("Invalid choice.nn");
        break;
    }
    printf("Enter a choice: ");
    scanf("%d", &choice);
    }
    printf("End of run.n");
    return 0;
}
void push(PassengerStackPtr* topPtr, int rowNum, char seatLetter, char* passengersName)
{
    PassengerStackPtr newPtr;
    newPtr = malloc(sizeof(PassengerStackPtr));
    if(newPtr != NULL) {
    newPtr->rowNumber = rowNum;
    newPtr->seat = seatLetter;
    newPtr->passengerName = passengersName;
    newPtr->nextPtr = *topPtr;
    *topPtr = newPtr;
    } else {
    printf("not inserted. No memory available.n");
    }
}
PassengerStackPtr pop(PassengerStackPtr* topPtr)
{

    PassengerStackPtr tempPtr;
    tempPtr = *topPtr;
    *topPtr = (*topPtr)->nextPtr;
    return tempPtr;
    free(tempPtr);
}
void top(PassengerStackPtr* topPtr)
{
}
void printStack(PassengerStackPtr currentPtr)
{
    if(currentPtr == NULL) {
    printf("The stack is empty.nn");
    } else {
    printf("The stack is:n");
    while(currentPtr != NULL) {
        printf("%d --> ", currentPtr->rowNumber);
        printf("%c --> ", currentPtr->seat);
        printf("%s --> ", currentPtr->passengerName);
        currentPtr = currentPtr->nextPtr;
    }
    printf("NULLnn");
    }
}
int full(PassengerStackPtr topPtr)
{
}
int empty(PassengerStackPtr topPtr)
{
    return topPtr == NULL;
}

Answer 1

newPtr->passengerName = passengersName;

这是不正确的，因为它会导致所有节点都指向同一地址。字符串不能在 C 中使用赋值进行复制。您需要使用类似 strdup 或 malloc 然后strcpy .

newPtr->passengerName = strdup(passengersName);

不要忘记在

不再需要这些字符串时free它们。