The document outlines decision-making statements in programming, specifically in C, including if statements, if-else statements, if-else ladders, nested if statements, and switch statements. It provides syntax explanations, algorithms, and examples for checking whether a number is positive or negative, and defining the day of the week based on user input. Flowcharts are also included to visually represent the algorithms discussed.

1. DECISION MAKING
STATEMENTS
Prof. Yashoda M B
Assistant Professor
Computer Science (UG)
Kristu Jayanti college
Bengaluru

2. if Statement
if- else Statement
if-else ladder
Nested if statement
switch statement
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3. if statement: Syntax
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4. Flowchart
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5. Algorithm: To check the number is positive.
Step 1: Start
Step 2: Read a number and store in the variable Num.
Step 3: If the number stored in the variable Num is grater
than 0, print “ The number is Positive”.
Step 4: Stop
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6. Example: C program to check the given number is positive.
#include<stdio.h>
#include<conio.h>
void main()
{
int Num;
clrscr();
printf(“enter a numbern”);
scanf(“%d”,&Num);
// if statement
if(Num>0)
printf(“The number is positive”);
getch();
}
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7. if-else statement: Syntax
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8. Flowchart
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9. Algorithm: To check the number is positive
or negative.
Step 1: Start
Step 2: Read a number and store in the variable Num.
Step 3: If the number stored in the variable Num is grater
than 0 go to Step 4, otherwise, go to step 5.
Step 4: print “ The number is Positive”. Goto Step 6.
Step 5: Print “The number is Negative”.
Step 6: Stop
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10. Example: C program to check the given number is positive or negative.
#include<stdio.h>
#include<conio.h>
void main()
{
int Num;
clrscr();
printf(“enter a numbern”);
scanf(“%d”,&Num);
// if else ladder
if(Num>0)
printf(“The number is positive”);
else
printf(“The number is negative”);
getch();
} 17/11/2023
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11. if-else ladder statement: Syntax
// any if-else ladder starts with an if statement only
if(condition1)
{
// statements
}
else if(condition2)
{
// this else if will be executed when condition in if is false and
// the condition of this else if is true
}
.... // once if-else ladder can have multiple else if
else
{
// at the end we put else
} 17/11/2023
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12. Flowchart
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13. Example: C program to check the given number is positive or negative.
#include<stdio.h>
#include<conio.h>
void main()
{
int Num;
clrscr();
printf(“enter a numbern”);
scanf(“%d”,&Num);
// if else ladder
if(Num>0)
printf(“The number is positive”);
else if(Num<0)
printf(“The number is negative”);
else
printf(“The number is zero”);
getch();
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14. nested if statement: Syntax
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15. Flowchart
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16. Example: C program to check the given number is positive or negative.
i) If positive, check whether if is odd or even
ii) if negative, display its square.
#include<stdio.h>
#include<conio.h>
void main() {
int Num;
clrscr();
printf(“enter a numbern”);
scanf(“%d”,&Num); // reading a number
if(Num>0)
{
printf(“The number is positive”);
if(Num%2==0) //nested if
printf(“The number is even”);
else
printf(“The number is odd”);
}
else {
printf(“The number is positive”);
printf(“The square of the number is %d”, Num*Num);
}
getch();
}
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17. switch statement: Syntax
switch(expression)
{
case value1: statement_1;
break;
case value2: statement_2;
break;
. . .
case value_n: statement_n;
break;
default: default_statement;
} 17/11/2023
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18. Flowchart
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19. Example: C program to display the day on user’s choice using switch statement.
#include<stdio.h>
#include<conio.h>
void main() {
int choice;
clrscr();
printf(“enter a choicen”);
scanf(“%d”,&choice); // reading a number
switch(choice) {
case 1: printf(“It is Monday”); break;
case 2: printf(“It is Tuesday”); break;
case 3: printf(“It is Wednesday”); break;
case 4: printf(“It is Thursday”); break;
case 5: printf(“It is Friday”); break;
case 6: printf(“It is Saturday”); break;
case 7: printf(“It is Sunday”); break;
default: printf(“Invalid choice”);
}
getch();
} 17/11/2023
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