吴裕雄--天生自然C语言开发：运算符

#include <stdio.h>
 
int main()
{
   int a = 21;
   int b = 10;
   int c ;
 
   c = a + b;
   printf("Line 1 - c 的值是 %d
", c );
   c = a - b;
   printf("Line 2 - c 的值是 %d
", c );
   c = a * b;
   printf("Line 3 - c 的值是 %d
", c );
   c = a / b;
   printf("Line 4 - c 的值是 %d
", c );
   c = a % b;
   printf("Line 5 - c 的值是 %d
", c );
   c = a++;  // 赋值后再加 1 ，c 为 21，a 为 22
   printf("Line 6 - c 的值是 %d
", c );
   c = a--;  // 赋值后再减 1 ，c 为 22 ，a 为 21
   printf("Line 7 - c 的值是 %d
", c );
 
}

#include <stdio.h>
 
int main()
{
   int c;
   int a = 10;
   c = a++; 
   printf("先赋值后运算：
");
   printf("Line 1 - c 的值是 %d
", c );
   printf("Line 2 - a 的值是 %d
", a );
   a = 10;
   c = a--; 
   printf("Line 3 - c 的值是 %d
", c );
   printf("Line 4 - a 的值是 %d
", a );
 
   printf("先运算后赋值：
");
   a = 10;
   c = ++a; 
   printf("Line 5 - c 的值是 %d
", c );
   printf("Line 6 - a 的值是 %d
", a );
   a = 10;
   c = --a; 
   printf("Line 7 - c 的值是 %d
", c );
   printf("Line 8 - a 的值是 %d
", a );
 
}

#include <stdio.h>
 
int main()
{
   int a = 21;
   int b = 10;
   int c ;
 
   if( a == b )
   {
      printf("Line 1 - a 等于 b
" );
   }
   else
   {
      printf("Line 1 - a 不等于 b
" );
   }
   if ( a < b )
   {
      printf("Line 2 - a 小于 b
" );
   }
   else
   {
      printf("Line 2 - a 不小于 b
" );
   }
   if ( a > b )
   {
      printf("Line 3 - a 大于 b
" );
   }
   else
   {
      printf("Line 3 - a 不大于 b
" );
   }
   /* 改变 a 和 b 的值 */
   a = 5;
   b = 20;
   if ( a <= b )
   {
      printf("Line 4 - a 小于或等于 b
" );
   }
   if ( b >= a )
   {
      printf("Line 5 - b 大于或等于 a
" );
   }
}

#include <stdio.h>
 
int main()
{
   int a = 5;
   int b = 20;
   int c ;
 
   if ( a && b )
   {
      printf("Line 1 - 条件为真
" );
   }
   if ( a || b )
   {
      printf("Line 2 - 条件为真
" );
   }
   /* 改变 a 和 b 的值 */
   a = 0;
   b = 10;
   if ( a && b )
   {
      printf("Line 3 - 条件为真
" );
   }
   else
   {
      printf("Line 3 - 条件不为真
" );
   }
   if ( !(a && b) )
   {
      printf("Line 4 - 条件为真
" );
   }
}

#include <stdio.h>
 
int main()
{
 
   unsigned int a = 60;    /* 60 = 0011 1100 */  
   unsigned int b = 13;    /* 13 = 0000 1101 */
   int c = 0;           
 
   c = a & b;       /* 12 = 0000 1100 */ 
   printf("Line 1 - c 的值是 %d
", c );
 
   c = a | b;       /* 61 = 0011 1101 */
   printf("Line 2 - c 的值是 %d
", c );
 
   c = a ^ b;       /* 49 = 0011 0001 */
   printf("Line 3 - c 的值是 %d
", c );
 
   c = ~a;          /*-61 = 1100 0011 */
   printf("Line 4 - c 的值是 %d
", c );
 
   c = a << 2;     /* 240 = 1111 0000 */
   printf("Line 5 - c 的值是 %d
", c );
 
   c = a >> 2;     /* 15 = 0000 1111 */
   printf("Line 6 - c 的值是 %d
", c );
}

#include <stdio.h>
 
main()
{
   int a = 21;
   int c ;
 
   c =  a;
   printf("Line 1 - =  运算符实例，c 的值 = %d
", c );
 
   c +=  a;
   printf("Line 2 - += 运算符实例，c 的值 = %d
", c );
 
   c -=  a;
   printf("Line 3 - -= 运算符实例，c 的值 = %d
", c );
 
   c *=  a;
   printf("Line 4 - *= 运算符实例，c 的值 = %d
", c );
 
   c /=  a;
   printf("Line 5 - /= 运算符实例，c 的值 = %d
", c );
 
   c  = 200;
   c %=  a;
   printf("Line 6 - %= 运算符实例，c 的值 = %d
", c );
 
   c <<=  2;
   printf("Line 7 - <<= 运算符实例，c 的值 = %d
", c );
 
   c >>=  2;
   printf("Line 8 - >>= 运算符实例，c 的值 = %d
", c );
 
   c &=  2;
   printf("Line 9 - &= 运算符实例，c 的值 = %d
", c );
 
   c ^=  2;
   printf("Line 10 - ^= 运算符实例，c 的值 = %d
", c );
 
   c |=  2;
   printf("Line 11 - |= 运算符实例，c 的值 = %d
", c );
 
}

#include <stdio.h>
 
int main()
{
   int a = 4;
   short b;
   double c;
   int* ptr;
 
   /* sizeof 运算符实例 */
   printf("Line 1 - 变量 a 的大小 = %lu
", sizeof(a) );
   printf("Line 2 - 变量 b 的大小 = %lu
", sizeof(b) );
   printf("Line 3 - 变量 c 的大小 = %lu
", sizeof(c) );
 
   /* & 和 * 运算符实例 */
   ptr = &a;    /* 'ptr' 现在包含 'a' 的地址 */
   printf("a 的值是 %d
", a);
   printf("*ptr 是 %d
", *ptr);
 
   /* 三元运算符实例 */
   a = 10;
   b = (a == 1) ? 20: 30;
   printf( "b 的值是 %d
", b );
 
   b = (a == 10) ? 20: 30;
   printf( "b 的值是 %d
", b );
}

#include <stdio.h>
 
main()
{
   int a = 20;
   int b = 10;
   int c = 15;
   int d = 5;
   int e;
 
   e = (a + b) * c / d;      // ( 30 * 15 ) / 5
   printf("(a + b) * c / d 的值是 %d
",  e );
 
   e = ((a + b) * c) / d;    // (30 * 15 ) / 5
   printf("((a + b) * c) / d 的值是 %d
" ,  e );
 
   e = (a + b) * (c / d);   // (30) * (15/5)
   printf("(a + b) * (c / d) 的值是 %d
",  e );
 
   e = a + (b * c) / d;     //  20 + (150/5)
   printf("a + (b * c) / d 的值是 %d
" ,  e );
  
   return 0;
}