lrint()函数使用当前的舍入模式将自变量中给出的分数值舍入为整数值。
在此，当前模式由函数fesetround()确定。
注意：此函数返回long int中的最终值。
用法:
lrint(double a); lrint(float a);
参数：
- lrint()函数采用双精度或浮点型或整数值作为参数。
返回：
- lrint()函数使用当前舍入模式将参数中给出的分数值舍入为整数值，并以long int形式返回值。在此，当前模式由函数fesetround()确定。默认情况下，舍入方向设置为“ to-nearest”。
可以使用fesetround()进行更改。
错误：
- 必须提供一个参数，否则将给调用“ lrint()”这样的错误提供不匹配的函数。
＃代码1
// CPP code to illustrate
// the functionality of lrint()
#include <cfenv>
#include <cmath>
#include <iostream>
using namespace std;
int main()
{
int a = 15;
long int answer;
// setting rounding direction to DOWNWARD
fesetround(FE_DOWNWARD);
answer = lrint(a);
cout << "Downward rounding of " << a
<< " is " << answer << endl;
return 0;
}输出：
Downward rounding of 15 is 15
＃代码2
// CPP code to illustrate
// the functionality of lrint()
#include <cfenv>
#include <cmath>
#include <iostream>
using namespace std;
int main()
{
double a;
long int answer;
// By default, the rounding direction
// is set to 'to-nearest'.
// fesetround(FE_TONEAREST)
a = 50.35;
answer = lrint(a);
cout << "Nearest rounding of " << a
<< " is " << answer << endl;
// mid values are rounded off to higher integer
a = 50.5;
answer = lrint(a);
cout << "Nearest rounding of " << a
<< " is " << answer << endl;
return 0;
}输出：
Nearest rounding of 50.35 is 50 Nearest rounding of 50.5 is 50
＃代码3
// CPP code to illustrate
// the functionality of lrint()
#include <cfenv>
#include <cmath>
#include <iostream>
using namespace std;
int main()
{
double a;
long int answer;
// Now, the rounding direction
// is set to UPWARD
fesetround(FE_UPWARD);
a = 50.3;
answer = lrint(a);
cout << "Upward rounding of " << a
<< " is " << answer << endl;
// Now, the rounding direction
// is set to DOWNWARD
fesetround(FE_DOWNWARD);
a = 50.88;
answer = lrint(a);
cout << "Downward rounding of " << a
<< " is " << answer << endl;
return 0;
}输出：
Upward rounding of 50.3 is 51 Downward rounding of 50.88 is 50
C++中的llrint()
llrint()函数使用当前的舍入模式将自变量中给出的分数值舍入为整数值。
在此，当前模式由函数fesetround()确定。
注意：因此函数以long long int返回值
用法:
llrint(double a); llrint(float a);
参数：
- llrint()函数采用双精度或浮点型或整数值作为参数。
返回：
- llrint()函数将自变量中给出的小数值舍入为
使用当前舍入模式的整数值，并在
long long int。
在此，当前模式由函数fesetround()确定。
默认情况下，舍入方向设置为“ to-nearest”。
可以使用fesetround()进行更改。
错误：
- 必须提供一个参数，否则将给调用“ llrint()”这样的错误提供不匹配的函数。
＃代码1
// CPP code to illustrate
// the functionality of llrint()
#include <cfenv>
#include <cmath>
#include <iostream>
using namespace std;
int main()
{
int a = 15;
long long int answer;
// setting rounding direction to DOWNWARD
fesetround(FE_DOWNWARD);
answer = llrint(a);
cout << "Downward rounding of " << a
<< " is " << answer << endl;
return 0;
}输出：
Downward rounding of 15 is 15
＃代码2
// CPP code to illustrate
// the functionality of llrint()
#include <cfenv>
#include <cmath>
#include <iostream>
using namespace std;
int main()
{
double a;
long long int answer;
// By default, the rounding direction is
// set to 'to-nearest'. fesetround(FE_TONEAREST)
a = 50.35;
answer = llrint(a);
cout << "Nearest rounding of " << a
<< " is " << answer << endl;
// mid values are rounded off to higher integer
a = 50.5;
answer = llrint(a);
cout << "Nearest rounding of " << a
<< " is " << answer << endl;
return 0;
}输出：
Nearest rounding of 50.35 is 50 Nearest rounding of 50.5 is 50
＃代码3
// CPP code to illustrate
// the functionality of llrint()
#include <cfenv>
#include <cmath>
#include <iostream>
using namespace std;
int main()
{
double a;
long long int answer;
// Now, the rounding direction
// is set to UPWARD
fesetround(FE_UPWARD);
a = 50.3;
answer = llrint(a);
cout << "Upward rounding of " << a
<< " is " << answer << endl;
// Now, the rounding direction is set to DOWNWARD
fesetround(FE_DOWNWARD);
a = 50.88;
answer = llrint(a);
cout << "Downward rounding of " << a
<< " is " << answer << endl;
return 0;
}输出：
Upward rounding of 50.3 is 51 Downward rounding of 50.88 is 50
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 lrint() and llrint() 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。