Expressions and Arithmetic

1
Expressions and Arithmetic
2
Assignments

• Due Lab 1
• Reading Chapter 3 3.1-3.4

3
Precision

• Describes number of columns to use when
  displaying number
• 5.2 lf number is right-justified
• -5.2lf number is left-justified
• If number is too small minimum number of
  columns will be used
• Decimal numbers are rounded
• Decimal point occupies a column as does (for
  negative numbers)

4
Precision Example

• include ltstdio.hgt int main(void)   
  double x 12345.6789      printf("10.2 -
  5.2lf\n", x)    printf("4.2 - 4.2lf\n", x)
     printf("5.6 - 5.6lf\n", x)    printf("15.6
  - 15.6lf\n", x)    printf("0.3 - 0.3lf\n",
  x)      return(0)

5
Precision Example

• include ltstdio.hgt int main(void)   
  double x 12345.6789      printf("10.2 -
  5.2lf\n", x) //12345.68
•    printf("4.2 - 4.2lf\n", x) //12345.68   
  printf("5.6 - 5.6lf\n", x) //12345.678900   
  printf("15.6 - 15.6lf\n", x) // 12345.678900
•    printf("0.3 - 0.3lf\n", x) //12345.679  
     return(0)

6
Arithmetic Expressions

• c a b
• d 12/6
• Binary Operators
• -
• /
• Unary Operator
• -

7
Examples

• 10 8
• 32 10
• 55 11

8
Expression Type

• Depends on operands
• int int -gt int
• double double -gt double
• int double -gt double
• int / int -gt ???

9
Precedence/Associativity

• Parentheses
• Unary operators
• , /,
• , - (binary)
• Binary evaluated left to right

10
Assignment

• total cost tax
• sum sum item -gt sum item
• mynum 5
• mynum 12

11
Errors

• Syntax
• printf(Hello, World!)
• Runtime
• x 0
• y 32/x
• Logic
• printf(Hell, World!)