在C++中,islessequal()是math.h中的预定义函数。用于检查第一个浮点数是否小于或等于第二个浮点。与简单比较相比,它提供的优势是,它在进行比较时不会引发浮点异常。例如,如果两个参数之一是NaN,则它返回false而不引发异常。
句法:
bool isgreaterequal(a, b)
Parameters:
- a, b => These two are the parameters whose value we want to compare.
Result:
- The function will return the true if a <= b else it returns false.
Error:
Exception:
- If a or b or both is NaN then the function raised an exception and return false(0).
对此的说明如下
// CPP code to illustrate
// the exception of function
#include
using namespace std;
int main()
{
// Take any values
float a = 5.5;
double f1 = nan("1");
bool result;
// Since f1 value is NaN so
// with any value of a, the function
// always return false(0)
result = islessequal(a, f1);
cout << a << " islessequal " << f1
<< ": " << result;
return 0;
}
输出:
5.5 islessequal nan: 0
例子:
- 程序1:
// CPP code to illustrate // the use of islessequal function #include
using namespace std; int main() { // Take two any values float a, b; bool result; a = 5.2; b = 8.5; // Since 'a' is less than // equal to 'b' so answer // is true(1) result = islessequal(a, b); cout << a << " islessequal to " << b << ": " << result << endl; int x = 8; int y = 5; // Since 'x' is not less // than equal to 'y' so answer // is false(0) result = islessequal(x, y); cout << x << " islessequal to " << y << ": " << result; return 0; } 注意:使用此函数,您还可以将任何数据类型与任何其他数据类型进行比较。
- 程式2:
// CPP code to illustrate // the use of islessequal function #include
using namespace std; int main() { // Take any two values bool result; float a = 80.23; int b = 82; // Since 'a' is less // than equal to 'b' so answer // is true(1) result = islessequal(a, b); cout << a << " islessequal to " << b << ": " << result << endl; char x = 'c'; // Since 'c' ascii value(99) is not // less than variable a so answer // is false(0) result = islessequal(x, a); cout << x << " islessequal to " << a << ": " << result; return 0; } 输出:
80.23 islessequal to 82: 1 c islessequal to 80.23: 0
应用范围:
在许多应用程序中,我们可以使用islessequal()函数比较两个值,例如在while循环中使用它来打印前10个自然数。
// CPP code to illustrate
// the use of islessequal function
#include
using namespace std;
int main()
{
int i = 1;
while (islessequal(i, 10)) {
cout << i << " ";
i++;
}
return 0;
}
输出:
1 2 3 4 5 6 7 8 9 10
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