[Flutter] num of Dart data type
1. Write in front
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2. Numeric type num
existdartlanguage, numeric typesnumberdivided into twointanddouble.
2.1 int type
void main ( ) {
numTest();
}
void numTest ( ) {
//number numeric int and double
num a = 1 ;
print ( a ) ;
}
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The results are as follows:
2.2 double type
void numTest ( ) {
//number numeric int and double
num a = 1 ;
print ( a ) ;
a = 3.4 ;
print ( a ) ;
}
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The results are as follows:
Need noton onedeclaration, can be used directlyintanddoubleAlso can.
void numTest ( ) {
//number numeric int and double
num a = 1 ;
print ( a ) ;
a = 3.4 ;
print ( a ) ;
int b = 4;
print(b);
double c = 3.3;
print(c);
}
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operation result:
doubleassignable typeintInteger,inttype is not assignabledouble.
2.3 Common methods
There are also some commonly used methods, such as judgmentodd numberstill iseven, subtraction, addition, multiplication and division (+ - * / ), modulo (%) and a special rounding (~/).
void numTest ( ) {
//number numeric int and double
num a = 1 ;
print ( a ) ;
a = 3.4 ;
print ( a ) ;
int b = 4;
print(b);
double c = 3 ; //equivalent to 3.0
print ( c ) ;
print ( b . isEven ) ; // is even
print ( b . isOdd ) ; // is odd
print ( b ~ / c ) ; // round up
}
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The results are as follows:
2.4 Type conversion
isEvenis even,isOddOdd or not, this is onlyinttype can only be called, thendoubleIf you want to call the type, you need to convert the type.
inttypes can also be converted todoubleYes, types can be converted to each other.
3. Write at the back
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