Question

这是一个计算房间里人们年龄的简单程序。我现在处于初始阶段，现在我看到我不知道哪些变量（我的意思是我在scanf之前声明的变量，然后是scanf中的占位符）用于scanf;如何选择和应用正确的变量。是否有资源可以用简单的英语解释这些问题？这是程序：

// Ages people by a year. Arrays

#include <stdio.h>

int main (void)
{
    // determine number of people
    int n;
    do
    {
        printf("Number of people in room: ");
        scanf ("%i", &n);
    }
    while (n<1); // get the number of people in the room, pass through user
                 // again and again until the user gives a positive integer

    // declare array in which to store everyone's age

    int ages[n];
    int  i;


    for (i = 0; i < n; i++)
    {
        printf("Age of person #%i: ", i + 1); // person number 1, person number 2, etc
        scanf ("%d", ages[i]); // store the age in the i-th part of the array ages
    }

    // report everyone's age a year hence
    printf("Time passes...\n\n");

    for (i = 0; i < n; i++)
    {
        printf(" A year from now person #%i will be %i years old.\n", i + 1, ages[i] + 1); 
        // we add 1 year to previous age

    }
 }

Answer 1

scanf("%d")期望一个地址作为参数。因此，请替换

scanf ("%d", ages[i]);

与

scanf ("%d", ages + i);

（或&ages[i]但这是个人偏好。）

Answer 2

scanf需要指向某个变量的指针才能更改它的值 - 否则会获得一些不会影响实变量的副本。

这一行： scanf ("%d", ages[i]); 取消引用ages并返回一个整数，而不是指向整数的指针。改变它 scanf ("%d", &ages[i]); &将提取ages[i]的内存地址并将其作为指针传递给scanf

数组和scanf问题;与scanf一起使用的值

2 个答案: