lrint()函數使用當前的舍入模式將自變量中給出的分數值舍入為整數值。
在此，當前模式由函數fesetround()確定。
注意：此函數返回long int中的最終值。
用法:
lrint(double a); lrint(float a);
參數：
- lrint()函數采用雙精度或浮點型或整數值作為參數。
返回：
- lrint()函數使用當前舍入模式將參數中給出的分數值舍入為整數值，並以long int形式返回值。在此，當前模式由函數fesetround()確定。默認情況下，舍入方向設置為“ to-nearest”。
可以使用fesetround()進行更改。
錯誤：
- 必須提供一個參數，否則將給調用“ lrint()”這樣的錯誤提供不匹配的函數。
＃代碼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;
}輸出：
Downward rounding of 15 is 15
＃代碼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;
}輸出：
Nearest rounding of 50.35 is 50 Nearest rounding of 50.5 is 50
＃代碼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;
}輸出：
Upward rounding of 50.3 is 51 Downward rounding of 50.88 is 50
C++中的llrint()
llrint()函數使用當前的舍入模式將自變量中給出的分數值舍入為整數值。
在此，當前模式由函數fesetround()確定。
注意：因此函數以long long int返回值
用法:
llrint(double a); llrint(float a);
參數：
- llrint()函數采用雙精度或浮點型或整數值作為參數。
返回：
- llrint()函數將自變量中給出的小數值舍入為
使用當前舍入模式的整數值，並在
long long int。
在此，當前模式由函數fesetround()確定。
默認情況下，舍入方向設置為“ to-nearest”。
可以使用fesetround()進行更改。
錯誤：
- 必須提供一個參數，否則將給調用“ llrint()”這樣的錯誤提供不匹配的函數。
＃代碼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;
}輸出：
Downward rounding of 15 is 15
＃代碼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;
}輸出：
Nearest rounding of 50.35 is 50 Nearest rounding of 50.5 is 50
＃代碼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;
}輸出：
Upward rounding of 50.3 is 51 Downward rounding of 50.88 is 50
相關用法
注：本文由純淨天空篩選整理自pawan_asipu大神的英文原創作品 lrint() and llrint() in C++。非經特殊聲明，原始代碼版權歸原作者所有，本譯文未經允許或授權，請勿轉載或複製。