Decision making with if statement and else..if

Decision making

what is decision making?

hello! everyone  today we are go in the order of execution of statement  based on certain condition,or a repeat a group of a statement until certain specified condition are met this involves a kind ofdecision making to see weather a particular condition has occured or not and then direct the computer to execute certain statement accordingly.

c language possess such decision making capabilities by supporting the following statements:g to study if statement and else...if statement.

we have seen that a C program is a set of a statement whicsituationh are normally executed sequentially in a order in which they appear.

we have a number of situation where we may have to change 

1.if statement

2. switch statement (will study in next tutorial)

3. conditional operator statement (will study in next tutorial)

4. go to statement (will study in next tutorial)

 

1. if statement

syntax- if (test expression)

if statement consist of a condition  and a test statement when this test condition is true then next statement will run.

Some example of decision making.using if statement :

1.if  (bank balance is zero)

Borrow money

2.if (room is dark)

Put on lights

3.if (code is 1)

Person is male

4.if (age is more than 50)

Person is retired

 

If statement may be implemented in different forms the different forms are:

1.simple if statement

2.if…..else statement

3.nested if…..else statement

4.else if ladder

1.Simple if statement

The general form of simple if statement is

if(test expression)

{

   Statement-block;

}

Statement-x;

2.if….else statement

The if…else statement is an extension of the simple if statement.the general forms is….

If(test expression)

{

      True-block statement(s)

}

Else

{

   False-block statement(S)

}

Statement-x

First we check 1st condition if this condition is false then compiler moves to else part to procced.

Example:-

// odd even by if else.......

 

#include<stdio.h>

main()

{

               int a;

               printf("enter the number u want to check:");

               scanf("%d",&a);

               if(a%2==0){

                              printf("given number is even:");

               }

               else printf("number is odd:");

              

               return 0;

}

 

3.Nesting of if…else statement

When a series of decision are involved we may have to use to more than one if…else statements

In nesting as shown here:

if(test conditon-1)

{

  if(test-2)

{

    Statement-1;

}

else

{

   Statement-2;

}

}

else

{

Statement-3;

}

Statement-x;

 

 

4. The else…if ladder

There is another way of putting ifs toegther when multipath decision are involved.a multiipath decision is a chian of ifs in which the each else is an if.it take following general form.

if (condition 1)

       Statement-1;

else if( condition 2)

        Statement-2;

else if(condition 3)

        Statement-3;

   else

      Default-statement;

Statement-x;

 

MCQs based on if ans else..if statement

1.what will be output of this  C code?

 #include <stdio.h>

void main()

    {

        int x = 0;

        if (x == 0)

            printf("hiii");

        else

            printf("how are you");

            printf("hellooo");

    }

 a) hi

b) how are you

c) hellooo

d) hihellooo

answer-d

2.what will be output of this  C code?

#include <stdio.h>
void main()
    {
        int x = 6;
        if (x < 1);
            printf("Helloo");
 
    }
a) Nothing
b) Run time error
c) Helloo
d) Varies

answer-c

3.what will be output of this  C code?

#include <stdio.h>
void main()
    {
        int x = 6;
        if (x < 1)
            printf("hello");
        if (x == 5)
            printf("hii");
        else
            printf("no");
    }
a) hi
b) hello
c) no
d) error

answer-a

4.what will be output of this  C code?
 
#include <stdio.h>
void main()
    {
        int x = 0;
        if (x++)
            printf("true\n");
        else if (x == 1)
            printf("false\n");
    }
a) true
b) false
c) compile time error
d) undefined behaviour

answer-b

5. What will be the output of following program ?
#include <stdio.h>
void main()
{
if(!printf(""))
printf("Okkkk");
else
printf("Hii");
}
        
a)Okkkk
b)Hiii
c)Error
d)None

answer-a



 


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