Computer Programming - if Statements & Relational Operators
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If statements and relational operators allow programmers to control program flow based on conditions. There are three types of if statements: if, if-else, and if-else-if. Relational operators like ==, <, > are used to form conditions. The if statement executes code if the condition is true, while if-else executes one block if true and another if false. Boolean logic and data type bool can be used to build more complex conditional expressions. Examples demonstrate using if statements and relational operators to check values, qualify ages to vote, and determine positive/negative numbers.
![RELATIONAL OPERATORS
Relational operators are 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](https://image.slidesharecdn.com/computerprogramming-ifstatementsrelationaloperators-180602011018/85/Computer-Programming-if-Statements-Relational-Operators-7-320.jpg)
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 • A conditional 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 IF STATEMENT • 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) Put multiple action statements within braces if (it's raining){ printf(“take umbrella”); printf(“wear raincoat”); }
- 6. ABSOLUTE VALUE // program to 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 operators are 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 A BLOCK 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(); }
- 17. SYNTAX OF IF-ELSE STATEMENT if ( condition) statement; else statement;
- 18. IF – ELSE WITH 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 OR NOT 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(); }