实型数据输出结果精确度

Question

float a=35.19; printf("%f\n%.2f\n", a, a); 为什么输出前者是35.189999，后者是35.19？

Answer 1

因为计算机里无法精确表示实型数据所以第一次输出的数据和35.19有误差输出35.189999，后面输出的时候格式输出为%.2f即保留两位小数，输出了35.19，你可以试试%.1f输出，就会输出35.2

Answer 2

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