c - getchar() 用于从输入中排除字符

Question

这就是我正在尝试做的事情: 我的老师给了我一个作业，要求我接收来自用户的输入，例如“1,2,3,4,-3,17,-9,0,5,-8,10”，并且在用户按下回车键后，程序应该忽略“，”符号并打印正数和负数(每个)的最大值和最小值。 现在他说我们应该使用 getchar() 来执行此操作，但我不明白如何...我知道这个函数用于从用户读取单个字符(而不是使用 putchar() 打印它)而不是用于忽略字符，所以我想了解如何使用它在 while 循环中执行此类操作。

因此，总结一下，我的问题是关于有选择地读取输入(其他事情我将自己管理，尽管如果有人在代码中看到某些内容并且可以给出提示，我会很高兴，但我希望了解 getchar() 函数做与我读到的设计目的相反的事情)，我已经编写和删除了代码数千次，但无法让它工作......这就是它现在的样子(并且它不起作用):

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

int main(){

char enter = "\n";
int list_of_nums[100];
char ch1[100];
int neg_num[100];
int pos_num[100];

printf("please enter numbers separated by ',': \n");


while (getchar()!= enter) {
    scanf("%d" ,&list_of_nums;
    if (list_of_nums >= 0){
        getchar();
       pos_num.append(list_of_nums);
    }
    else{
                neg_num.append(list_of_nums);

        }
}



 int max_pos = max.pos_num[];
 int min_pos = min.pos_num[];
 int max_neg = max.neg_num[];
 int min_pos = min.neg_num[];

 printf("the maximum number of all the positives is: %d \n" ,max_pos);
 printf("the minimum number of all the positives is: %d \n" ,min_pos);
 printf("the maximum number of all the negatives is: %d \n" ,max_neg);
 printf("the minimum number of all the negatives is: %d \n" ,min_neg);


 return 0;



}

Answer 1

根据第一个输入选择下一个输入中发生的情况。这是负数的代码。只需添加两位数的情况并优化即可:

#include <stdio.h>
#include <stdlib.h>
#define MAX_NUMBERS 100

int main(void){
    int list_of_nums[MAX_NUMBERS];
    int pos_nums[MAX_NUMBERS];
    int neg_nums[MAX_NUMBERS];
    int size = 0, size_pos = 0, size_neg = 0, i, max_pos, min_pos, max_neg, min_neg, neg_flag = 0;
    char input;

    printf("Enter numbers separated by ',':\n");

    do {
        input = getchar();
        if(input == '-') {
            neg_flag = 1;   //for negative numbers
            input = getchar();
        }
        if(input >= '0' && input <= '9') {
            if(neg_flag) {
                list_of_nums[size] = -(input - 48); //FROM ASCII CHARACTER CODE
            } else {
                list_of_nums[size] = input - 48;
            }
            neg_flag = 0;
            size++;
        } else {
            neg_flag = 0;
        }
    } while(input != '\n');

    for(i = 0; i < size; i++) {
        printf("%d ", list_of_nums[i]);
        if(list_of_nums[i] >= 0) {
            pos_nums[size_pos] = list_of_nums[i];
            size_pos++;
        }
        else {
            neg_nums[size_neg] = list_of_nums[i];
            size_neg++;
        };
    }
    printf("\n");

    max_pos = pos_nums[0];
    min_pos = pos_nums[0];
    for(i = 1; i < size_pos; i++) {
        if(max_pos < pos_nums[i]) max_pos = pos_nums[i];
        if(min_pos > pos_nums[i]) min_pos = pos_nums[i];
    }

    max_neg = neg_nums[0];
    min_neg = neg_nums[0];
    for(i = 1; i < size_neg; i++) {
        if(max_neg < neg_nums[i]) max_neg = neg_nums[i];
        if(min_neg > neg_nums[i]) min_neg = neg_nums[i];
    }

    printf("The maximum number of all the positives is: %d\n", max_pos);
    printf("The minimum number of all the positives is: %d\n", min_pos);
    printf("The maximum number of all the negatives is: %d\n", max_neg);
    printf("The minimum number of all the negatives is: %d\n", min_neg);

    return 0;
}

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