Decision Making and Looping

C supports Decision Making and Looping (Interations)

In decision Making,

if, if-else, if- else if – else, switch – case is used.

if(condition)

{

//These statements are executed only if the condition is true or 1

}

if – else

if(condition)

{

//These statements are executed only if the condition is true or 1

}

else

{

//these statement are executed only if the condition is false or 0

}

(in the above example, there is no else part means that for some situation, there may not be a need for else part)

if – else if – else

if(condition 1)

{

//These statements are executed if the condition 1 is true or 1

}

else if (condition 2)

{

//These statements are executed if the condition 2 is true or 1

}

else

{

//These statements are executed neither condition 1 nor condition 2 are true

// if all the conditions fails, then this statement will execute

}

Switch Case

switch (expression)

{

case 1: statement 1;

break;

case 2: statement 2;

break;

case 3: statement 3;

break;

default: statement d;

break;

}

//Statement n;

The switch case works similar like a multiple if else if statement.

Assume if the expression takes 3 as the value and the statement 3 will be executed and next there is a break statement, so the control comes to statement n and it ill be printed.

so when case 3: is success, then

statement 3;

statement n;

will be printed

Looping

  • while()
  • do .. while();
  • for()

while ()

while(condition)

{

//statement 1

}

statement 1 will keep on execution till the condition becomes false

so this loop is called as entry controlled loop

do while()

do

{

//Statement 1

}while(condition);

in this, whether the condition is true or false, first time the loop will execute and only then it will check for validity of the condition.

so this loop is called as exit controlled loop

for loop

for (initialization: condition; increment/decrement)

{

//Statement

}

More details about the looping will be in subsequent posts.

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