Computer Programming - if Statements & Relational Operators

Computer Programming - if Statements & Relational Operators

• 1.
  PROGRAMMING IF STATEMENTS & RELATIONAL OPERATORS By:John Paul Espino De La Salle University – Dasmarinas Facebook.com/Johnpaul.dss
• 3.
  CONDITIONAL STATEMENTS • Aconditional statement allows us to control whether a program segment is executed or not. • Two constructs • if statement • if • if-else • if-else-if • switch statement
• 4.
  THE BASIC IFSTATEMENT • Syntax if(condition) action • if the condition is true then execute the action. • action is either a single statement or a group of statements within braces. condition action true false
• 5.
  CHOICE (IF)  Putmultiple action statements within braces if (it's raining){ printf(“take umbrella”); printf(“wear raincoat”); }
• 6.
  ABSOLUTE VALUE // programto read number & print its absolute value #include <stdio.h> main(){ int value; printf("Enter integer: “); scanf(“%d”,&value); if(value < 0) value = -value; printf("The absolute value is %d “,value); getch(); }
• 7.
  RELATIONAL OPERATORS Relational operatorsare used to compare two values to form a condition. Math C Plain English = == equals [example: if(a==b) ] [ (a=b) means put the value of b into a ] < < less than  <= less than or equal to > > greater than  >= greater than or equal to  != not equal to
• 8.
  CONDITIONS Examples: Number_of_Students < 200 10> 20 20 * j == 10 + i
• 9.
  THE BOOLEAN TYPE •C contains a type named bool for conditions. • A condition can have one of two values: • true (corresponds to a non-zero value) • false (corresponds to zero value) • Boolean operators can be used to form more complex conditional expressions. • The and operator is && • The or operator is || • The not operator is !
• 10.
  THE BOOLEAN TYPE •Truth table for "&&" (AND): Operand1 Operand2 Operand1 && Operand2 true true true true false false false true false false false false
• 11.
  THE BOOLEAN TYPE •Truth table for “||" (OR): Operand1 Operand2 Operand1 || Operand2 true true true true false true false true true false false false
• 12.
  THE BOOLEAN TYPE •Truth table for "!" (NOT): Operand !Operand true false false true
• 13.
  A BOOLEAN TYPE •Assignments to bool type variables bool P = true; bool Q = false; bool R = true; bool S = P && Q; bool T = !Q || R; bool U = !(R && !Q);
• 14.
  “IF” WITH ABLOCK OF STATEMENTS if (aValue <= 10) { printf("Answer is %.2fn", aValue); countB++; }
• 15.
  POSITIVE OR NEGATIVE #include<stdio.h> main() { int number; clrscr(); printf(“Enter a number”); scanf(“%d”,&number); if (number>0) printf(“It is Positive”); getch(); }
• 16.
  IF-ELSE STATEMENT
• 17.
  SYNTAX OF IF-ELSESTATEMENT if ( condition) statement; else statement;
• 18.
  IF – ELSEWITH A BLOCK OF STATEMENTS if (aValue <= 10) { printf("Answer is %.2fn", aValue); countB++; } End if else { printf("Error occurredn"); countC++; } End else
• 19.
  TO VOTE ORNOT TO VOTE #include<stdio.h> main() { int age; clrscr(); printf(“Enter your age”); scanf(“%d”,&age); if (age>=18) printf(“You are qualified to vote”); else printf(“Not qualified to vote”); getch(); }
• 20.
  POSITIVE OR NEGATIVE #include<stdio.h> main() { int number; clrscr(); printf(“Enter a number”); scanf(“%d”,&number); if (number>0) printf(“Positive number”); else printf(“Negative number”); getch(); }