c - 如何在 C 中显示消息或响应无效输入

Question

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

int main()
{
    int a, result;
    float b;
    printf("**This is a simple arithmetic calculator.** \n");
    printf("\n Please enter an integer: ");
    scanf("%i ", a);
    printf("Please enter a floating point number: ");
    scanf("%f", b);

    result = a + b

    printf("Output: ");
    printf("%i + %f = %lf \n", a, b, result);
    printf("%i - %f = %lf \n", a, b, result);
    printf("%i * %f = %lf \n", a, b, result);
}

我需要确保您的程序不会在用户输入无效输入时崩溃。

Answer 1

scanf 是一个函数，它也有一个返回值，指示正确插入了多少输入。所以你可以做类似的事情:

while (scanf("%i ", a) != 1)
{
   printf("wrong input, try again");
}