isnan函数 c语言
C ++ isnan()函数 (C++ isnan() function)
isnan() functionis a library function ofcmathheader, it is used to check whether the given value is a NaN (Not-A-Number). It accepts a value (float, double or long double) and returns 1 if the given value is NaN; 0, otherwise.
isnan()函数是cmath标头的库函数，用于检查给定的值是否为NaN(非数字)。 它接受一个值( float ， double或long double )，如果给定值为NaN，则返回1；否则，返回1。 0，否则。
Syntax of isnan() function:
isnan()函数的语法：
In C99, it has been implemented as a macro,
在C99中，它已实现为宏，
macro isnan(x)
In C++11, it has been implemented as a function,
在C ++ 11中，它已作为函数实现，
bool isnan (float x);bool isnan (double x);bool isnan (long double x);
Parameter(s):
参数：
x – represents a value to be checked as a NaN.
x –表示要检查为NaN的值。
Return value:
返回值：
The returns type of this function is bool, it returns 1 if the x is NaN; 0, otherwise.
该函数的返回类型为bool ，如果x为NaN，则返回1；否则，返回1。 0，否则。
Example:
例：
Input:float x = 0.0f/0.0f;Function call:isnan(x); Output:1Input:float x = sqrt(-1.0f);Function call:isnan(x); Output:1Input:float x = 10.0f;Function call:isnan(x); Output:0
C ++代码演示isnan()函数的示例 (C++ code to demonstrate the example of isnan() function)
// C++ code to demonstrate the example of// isnan() function#include <iostream>#include <cmath>using namespace std;int main(){cout << "isnan(sqrt(-10.0f)): " << isnan(sqrt(-10.0f)) << endl;cout << "isnan(0.0f/0.0f): " << isnan(0.0f / 0.0f) << endl;cout << "isnan(0.0f/1.0f): " << isnan(0.0f / 1.0f) << endl;cout << "isnan(1.0f/0.0f): " << isnan(1.0f / 0.0f) << endl;float x = sqrt(-1.0f);// checking using the conditionif (isnan(x)) {cout << x << " is a NaN." << endl;}else {cout << x << " is not a NaN." << endl;}x = sqrt(2);if (isnan(x)) {cout << x << " is a NaN." << endl;}else {cout << x << " is not a NaN." << endl;}return 0;}
Output
输出量
isnan(sqrt(-10.0f)): 1isnan(0.0f/0.0f): 1isnan(0.0f/1.0f): 0isnan(1.0f/0.0f): 0-nan is a NaN.1.41421 is not a NaN.
Reference: C++ isnan() function
参考： C ++ isnan()函数
翻译自: /cpp-tutorial/isnan-function-with-example.aspx
isnan函数 c语言
