124.md

C 程序：在结构中动态存储数据

原文： https://www.programiz.com/c-programming/examples/structure-dynamic-memory-allocation

在此示例中，您将学习存储用户使用动态内存分配输入的信息。

要理解此示例，您应该了解以下 C 编程主题：

• C 指针
• C 动态内存分配
• C 结构

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该程序要求用户存储noOfRecords的值，并使用malloc()函数为noOfRecords结构变量动态分配内存。

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演示结构的动态内存分配

#include <stdio.h>
#include <stdlib.h>
struct course {
    int marks;
    char subject[30];
};

int main() {
    struct course *ptr;
    int i, noOfRecords;
    printf("Enter the number of records: ");
    scanf("%d", &noOfRecords);

    // Memory allocation for noOfRecords structures
    ptr = (struct course *)malloc(noOfRecords * sizeof(struct course));
    for (i = 0; i < noOfRecords; ++i) {
        printf("Enter the name of the subject and marks respectively:\n");
        scanf("%s %d", &(ptr + i)->subject, &(ptr + i)->marks);
    }

    printf("Displaying Information:\n");
    for (i = 0; i < noOfRecords; ++i)
        printf("%s\t%d\n", (ptr + i)->subject, (ptr + i)->marks);

    return 0;
} 

输出

Enter the number of records: 2
Enter the name of the subject and marks respectively:
Programming
22
Enter the name of the subject and marks respectively:
Structure
33

Displaying Information:
Programming      22
Structure        33