C/C++ abs(), labs(), llabs()用法及代码示例

在cstdlib头文件中定义了abs()，labs()，llabs()函数。这些函数返回作为其参数输入到它们的整数的绝对值。

1. abs()函数：此函数的输入是C中int类型的值和C++中int类型，long int或long long int的值。在C中，输出是int类型，在C++中，输出具有与输入相同的数据类型。下面是示例C++程序，以显示abs()函数的工作。

   // CPP program to illustrate 
   // abs() function 
   #include <cstdlib> 
   #include <iostream> 
     
   using namespace std; 
     
   int main() 
   { 
       int val1, val2; 
     
       /// finding absolute value using 
       /// abs() function. 
       val1 = abs(22); 
       val2 = abs(-43); 
     
       cout << "abs(22) = " << val1 << "\n"; 
       cout << "abs(-43) = " << val2 << "\n"; 
       return 0; 
   }

   Output:
   abs(22) = 22
   abs(-43) = 43
   

2. labs()函数：这是abs()函数的long int版本。输入和输出均为long int类型。下面是示例C++程序，以显示labs()函数的工作。 post_top_responsive

   // CPP program to illustrate 
   // labs() function 
   #include <cstdlib> 
   #include <iostream> 
     
   using namespace std; 
     
   int main() 
   { 
       int val1, val2; 
     
       /// finding absolute value using 
       /// labs() function. 
       val1 = labs(1234355L); 
       val2 = labs(-4325600L); 
     
       cout << "labs(1234355L) = " << val1 << "\n"; 
       cout << "labs(-4325600L) = " << val2 << "\n"; 
       return 0; 
   }

   Output:
   labs(1234355L) = 1234355
   labs(-4325600L) = 4325600
   

3. llabs()函数：这是abs()函数的long long int版本。输入和输出均为long long int类型。下面是示例C++程序，以显示llabs()函数的工作。

   // CPP program to illustrate 
   // llabs() function 
   #include <cstdlib> 
   #include <iostream> 
     
   using namespace std; 
     
   int main() 
   { 
       int val1, val2; 
     
       /// finding absolute value using 
       /// labs() function. 
       val1 = llabs(1234863551LL); 
       val2 = llabs(-432592160LL); 
     
       cout << "llabs(1234863551LL) = " << val1 << "\n"; 
       cout << "llabs(-432592160LL) = " << val2 << "\n"; 
       return 0; 
   }

   Output:
   llabs(1234863551LL) = 1234863551
   llabs(-432592160LL) = 432592160