将货币值作为 float 进行比较不起作用

Question

如果我输入 0.01 或 0.02，程序会立即退出。我该怎么办？

#include <stdio.h>

char line[100];
float amount;

int main()
{
printf("Enter the amount of money: ");
fgets(line, sizeof(line), stdin);
sscanf(line, "%f", &amount);

if (amount == 0.0)
    printf("Quarters: 0\nDimes: 0\nNickels: 0\nPennies: 0");

if (amount == 0.01)
   printf("Quarters: 0\nDimes: 0\nNickels: 0\nPennies: 1");


if (amount == 0.02)
   printf("Quarters: 0\nDimes: 0\nNickels: 0\nPennies: 2");

return (0);
}

Answer 1

What is the most effective way for float and double comparison?

你应该使用这样的东西

bool isEqual(double a, double b)
{
    return fabs(a - b) < EPSILON;
}

或者这个

#define ISEQUAL(a,b) ( fabs((a) - (b)) < EPSILON)

并定义EPSILON

#define EPSILON (0.000001)