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# Chapter-6(Decision-Making Statements)

1.Conditional Statements:-

a)If Statements:-

The if statement is used to execute a block of statements if a specified condition is true.

Syntax:-

if(condition)

{

Statement 1;

}

Statement 2;

If the condition is true, then statement 1 is executed; otherwise, statement 2 is executed.

b) If-else Statements:-

It allows you to execute different blocks of code based on whether a specified condition is true or false.

Syntax:-

if(condition)

{

Statement 1;

}

else

{

Statement 2;

}

If the condition is true, then the if statement (Statement 1) is executed; otherwise, the else statement (Statement 2) is executed.

c) Multiple-If Statement:

syntax:-

if(condition)

{

Statement1;

}

else if(condition)

{

Statement2;

}

else

{

Statement3;

}

multiple`if` statements to check multiple conditions sequentially. Each`if` statement is evaluated independently, and the corresponding block of code is executed if the condition is true.

d) Nested If Statement:

A nested if statement is an if statement that appears within the body of another if or else statement. This allows for more complex conditions and decision-making structures in a program. Here is the syntax and an example of a nested if statement in C

if (condition1)

{

//--Statement 1 is executed if condition1 is true

Statement1;

if (condition2)

{

//-- Statement2 is executed if both condition1 and condition2 are true

Statement2;

}

//-- More code you can execute outside of if block

}

else

{

//-- Statement3 is executed if condition1 is false

Statement3;

if (condition3)

{

//--Statement 4 is executed if condition3 is true

Statement4;

}

else

{

//-- Statement5 to be executed if both condition1 and Condition 3 are false.

Statement5;

}

// More code you can execute within the outer else block

}

// Code  you can execute outside the if-else blocks

e) Conditional/Teenary Expression:-

syntax:-

Expression1?Expression2:Expression3;

• a) Expression1: A boolean expression that is evaluated
• b) Expression2: The value or expression2 to be returned if Expression1 is true.
• c) Expression3: The value or expression3 to be returned if Expression1 is false.

In this example, the ternary expression (number >= 0) ? "positive" : "negative" checks if the number is greater than or equal to 0. If true, the expression evaluates to "positive"; otherwise, it evaluates to "negative".

f)Switch Statement:-

The switch statement in C provides a way to handle multiple cases based on the value of an expression.

Syntax:-

switch (expression)

{

case value1:

// Block of code to be executed if expression equals value1;

break;

case value2:

// Block of code to be executed if expression equals  value2;

break;

default:

// block of code to be executed if none of the cases match the expression;

}

a) expression: the variable or value that is being tested.

b) case value 1: The first case to check. If the expression equals value 1, the code within this case is executed.

c) break: Terminates the switch statement. If omitted, execution will continue to the next case without checking for further matches.

d) default: If none of the cases match, the default block's code is executed.

Example:-

#include <stdio.h>

#include <conio.h>

void main() {

case 'A':

printf("Excellent!\n");

break;

case 'B':

printf("Good!\n");

break;

case 'C':

printf("Satisfactory.\n");

break;

case 'D':

printf("Needs Improvement.\n");

break;

default:

}

getch();

}

a). The user is prompted to enter a grade ('A', 'B', 'C', 'D').

b). To check the value of grade, the program uses a switch statement.

c). Based on the value of grade, it executes the corresponding case block.

Note: The break statement is used to exit the switch statement after a case is executed. If the break is omitted, execution will continue to the next case.

2. Unconditional Statements:

a)Break Statement:-

It is used to terminate the loop.

The break statement is used to terminate the execution of the innermost loop (for, while, or do-while).

syntax:-

for (initialization; condition; alteration) {

// Statement to be executed in each iteration

if (condition_to_out of loop) {

break; // Exit the loop prematurely

}

}

b)Continue Statement:-

It is used to skip the number of terms.

In C programming, the continue statement is used to skip the rest of the code inside a loop for the current iteration and move on to the next iteration of the loop. It is typically used within loops (for, while, or do-while) to jump to the next iteration prematurely.

Syntax:-

for (initialization; condition; alteration)

{

// block of code before the continue statement

if (condition_to_skip)

{

continue; // Skip the rest of the block of code in the current alteration and move to the next alteration

}

// code after the continue statement

}

when (condition_to_skip) is true  then it skip current alteration and move to next alteration.

c) goto Statement:-

It is used to jump the control from one statement to another.

Example:-

int i;

for(i=1; i<=10; i++)

{

if(i==5)

{

goto label1;

}

printf("%d\n",i);

}

printf("out of loop");

label1:

printf("Hello");

Result:-

2

3

4

Hello

Conclusion:-

label: It is a user-defined identifier followed by a colon (`:`). The label is a target for the`goto` statement, indicating the position in the code where control should be transferred.

Here we use label1 in the example instead of label.

3. Repetitive statement:-

Repetitive statements, also known as loops, are used to execute a block of code repeatedly as long as a certain condition is true. There are three main types of loops in the C language: for, while, and do-while. Each type serves different purposes but shares the common objective of repetitive execution.

a). For Loop:

The for loop is typically used when the number of iterations is known beforehand.

Steps to work for loop:

1. Intialization

2.Condition

3. Body of loop

4. Alteration

Syntax:-

for (initialization; condition; Alteration)

{

Body of the loop;

}

Example:-

int i;

for(i=1;i<=5;i++)

{

printf("%d",i);

}

Result:-

1

2

3

4

5

b)While Loop:-

The while loop is used when the number of iterations is not known beforehand, and the loop continues as long as a specified condition is true.

syntax:-

While(condition)

{

Body of loop;

}

Example:-

int i=1;

while(i<=5)

{

printf("%d\n",i);

i++;

}

Result:-

1

2

3

4

5

c)do-while loop:-

The do-while loop is similar to the while loop, but it ensures that the loop body is executed at least once before the condition is checked.

Syntax:-

do

{

Body of loop;

}

while(condition);

Example:-

int i=1;

do

{

printf("%d\n",i);

i++;

}

while(i<=5);

Result:-

1

2

3

4

5