fdim()函数采用两个参数，并返回第一个和第二个参数之间的正差。
如果a> b否则返回0，则此函数返回a-b。其中，a是第一个参数，b
是第二个参数。
用法:
double fdim(double a, double b); float fdim(float a, float b);
参数：
The fdim() function takes two arguments a and b, where, a is the first argument and b is the second argument.
返回：
This function returns a-b if a>b otherwise returns 0.
错误：
It is mandatory to give both the arguments otherwise it will give error no matching function for call to 'fdim()' like this.
例子：
Inuput : fdim(2.0, 1.0) Output : 1 Inuput : fdim(-2.0, 1.0) Output : 0
＃代码1
#include <cmath>
#include <iostream>
using namespace std;
int main()
{
// positive difference for 2.0 and 1.0 is 1
cout << "fdim of (2.0, 1.0) is " << fdim(2.0, 1.0) << endl;
// here 1.0<2.0 so the output is 0
cout << "fdim of (1.0, 2.0) is " << fdim(1.0, 2.0) << endl;
// here -2.0<-1.0 so the output is 0
cout << "fdim of (-2.0, -1.0) is " << fdim(-2.0, -1.0) << endl;
// positive difference for -1.0 and -2.0 is 1
cout << "fdim of (-1.0, -2.0) is " << fdim(-1.0, -2.0) << endl;
return 0;
}输出：
fdim of (2.0, 1.0) is 1 fdim of (1.0, 2.0) is 0 fdim of (-2.0, -1.0) is 0 fdim of (-1.0, -2.0) is 1
＃代码2
#include <cmath>
#include <iostream>
using namespace std;
int main()
{
// positive difference for 5.0 and 4.0 is 1
cout << "fdim of (5.0, 4.0) is " << fdim(5.0, 4.0) << endl;
// here 4.0<5.0 so the output is 0
cout << "fdim of (4.0, 5.0) is " << fdim(4.0, 5.0) << endl;
// here -5.0<-4.0 so the output is 0
cout << "fdim of (-5.0, -4.0) is " << fdim(-5.0, -4.0) << endl;
// positive difference for 5.0 and 4.0 is 1
cout << "fdim of (-4.0, -5.0) is " << fdim(-4.0, -5.0) << endl;
return 0;
}输出：
fdim of (5.0, 4.0) is 1 fdim of (4.0, 5.0) is 0 fdim of (-5.0, -4.0) is 0 fdim of (-4.0, -5.0) is 1
相关用法
注：本文由纯净天空筛选整理自pawan_asipu大神的英文原创作品 fdim() in C++。非经特殊声明，原始代码版权归原作者所有，本译文未经允许或授权，请勿转载或复制。