4、 C language operators

1、 Operator classification

• Arithmetic operator
  • %： Modulo operators , The remainder after division , Integer only , It can't be a decimal , The result symbol depends on % The symbol on the left
• Relational operator
  • be equal to 、 It's not equal to 、 Greater than 、 Less than 、 Greater than or equal to 、 Less than or equal to
• Logical operators
  • &&： Logic and computation
  • ||： Logic or operation
  • ！： Logical nonoperator
• An operator
  • &： Bitwise AND
  • |： Press bit or
  • ^： Exclusive or operation
  • ~： Reverse operation
    • ~1 = -2
    • ~0 = -1
  • <<: Shift left operator , The right to repair 0
  • />>: Shift right operator , Positive left to fill 0, Negative left to fill 1
• Assignment operator

Operator	effect
=	c = a+b
c+=a	c=c+a
c-=a	c=c-a
c*=a	c=c*a
c/=a	c=c/a
c%=a	c=c%a
c<<=2	c=c<<2
c>>=2	c=c>>2
c&=2	c=c&2
c^=2	c=c^2
c|=2	c=c|2

• Miscellaneous operators
  • sizeof()： Returns the size of the variable
  • &： Return the address of the variable
  • *： Point to a variable
  • ？：： Conditional expression , Ternary operator

2、 Detailed explanation of operation

1.a++ and ++a The difference between

• Code implementation ：

  #include<stdio.h>
  
  int main(){
        
      int c;
      int a = 10;
      c = a++;//c As the result of the 10
      printf(" Operation after assignment :%d\n",c);
  
      a = 10;
      c = ++a;//c As the result of the 11
      printf(" Evaluate first and then assign :%d",c);
  }
  

• Running results ：

   Operation after assignment :10
   Evaluate first and then assign :11
  

2. An operator

• Code implementation ：

  #include<stdio.h>
  #include<stdlib.h>
  
  void binary(int x){
        
      int b,i,k = 0;
      int remainder[30];
      while (x != 0)      
      {
        
          b = x/2;
          k++;
          remainder[k] = x - b*2;
          x = x/2;
      }
      for(i = k;i >= 1;i--){
        
          printf("%d",remainder[i]);
          
      }
      printf("\n");
      
  }
  
  int main(){
        
      unsigned int a = 60; //00111100
      unsigned int b = 13; //00001101
      int c = 0;
      c = a & b;
      printf("a,b Bitwise AND ：");
      binary(c);
      c = a | b;
      printf("a,b Press bit or ：");
      binary(c);
      c = a ^ b;
      printf("a,b Bitwise XOR ：");
      binary(c);
      c = ~a;
      printf("a Take the opposite ：");
      binary(c);
      printf("a Take the opposite ：%d\n",c);
      c = a << 2;
      printf("a Move two places to the left ：");
      binary(c);
      c = a >> 2;
      printf("a Move two places to the right ：");
      binary(c);
      
  }
  

• Running results ：

  a,b Bitwise AND ：1100
  a,b Press bit or ：111101
  a,b Bitwise XOR ：110001
  a Take the opposite ：-1-1-1-10-1
  a Take the opposite ：-61
  a Move two places to the left ：11110000
  a Move two places to the right ：1111
  

3. Miscellaneous operators

• Code implementation ：

  #include<stdio.h>
  
  int main(){
        
      int a = 4;
      short b;
      double c;
      int *ptr;// Define a pointer 
      printf("a Size ：%ld\n",sizeof(a));
  
      ptr = &a;// take a Address assigned to ptr
      printf("*ptr Value :%d\n",*ptr);// Take the value corresponding to the address 
  
      a = 10;
      b = (a == 10) ? 20 : 30;// Ternary operator 
      printf("b Value ：%d",b);
  }
  

• Running results ：

  a Size ：4
  *ptr Value :4
  b Value ：20
  

4. In calculator , Negative numbers exist in the form of complements of their positive values

• Source code ：0001
• Inverse code ：1110
• Complement code ： Counter code plus 1 1111

5. ~ operation

• effect ： According to the not
• Code implementation ：

  #include<stdio.h>
  #include<stdlib.h>
  
  int main(){
        
      int b = 13; //00001101
      printf("%x",~b);
  }
  

• Running results ：

  fffffff2 //11110010