principal of programming language unit 3 explanation

principal of programming language unit 3 explanation

• 1.
  UNIT 3
• 6.
  • #include<stdio.h> • main( ){ • int a= 10, b = 20; • printf (" %d", a<b); • printf (" %d", a<=b); • printf (" %d", a>b); • printf (" %d", a>=b); • printf (" %d", a = =b); • printf (" %d", a ! =b); • }
• 7.
  Logical Operators • Theseare used to combine 2 (or) more expressions logically. • They are logical AND (&&) logical OR ( || ) and logical NOT (!) • main ( ){ • int a= 10, b = 20, c= 30; • printf (" %d", (a>b) && (a<c)); • printf (" %d", (a>b) | | (a<c)); • printf (" %d", ! (a>b));
• 8.
  • A short-circuitevaluation of an expression is one in which the result is determined without evaluating all of the operands and/or operators. • For example, the value of the arithmetic expression • (13 * a) * (b / 13 - 1) • is independent of the value of (b / 13 - 1) if a is 0 , because 0 * x = 0 for any x . So, when a is 0 , there is no need to evaluate (b / 13 - 1) or perform the second multiplication. However, in arithmetic expressions, this shortcut is not easily detected during execution, so it is never taken.
• 9.
  • Problem withnon-short-circuit evaluation index = 0; while (index <= length)&& (LIST[index] != value) index++; • When index=length, LIST[index] will cause an indexing problem (assuming LIST is length - 1 long)
• 10.
  A>B || (B++)/3
• 11.
  • C, C++,and Java: use short-circuit evaluation for the usual Boolean operators (&& and ||), but also provide bitwise Boolean operators that are not short circuit (& and |) • All logic operators in Ruby, Perl, ML, F#, and Python are short-circuit evaluated • Ada: programmer can specify either (short-circuit is specified with and then and or else)
• 12.
  Mixed-Mode Assignment • Assignmentstatements can also be mixed mode • In Fortran, C, Perl, and C++, any numeric type value can be assigned to any numeric type variable • In Java and C#, only widening assignment coercions are done • In Ada, there Is no assignment coercion Widening refers to assigning a value from a smaller or more specific type to a larger or more general type. This is considered safe because it avoids data loss. int num = 100; double d = num; // Widening: int to double (allowed) The integer value 100 is being widened to a double, and since a double can represent integers safely, this is allowed without explicit casting.