Selection statements

Sunday, 14 August 2016

Selection statement:

  • selection statement executes one or more statements based on condition or expression.
  • selection statements are also called conditional statements or branching statements.
       c-language supports a set of selection statements has following
  • if  statement
  • if else statements
  • nested if ...else statement
  • if....else if statement
  • switch

     if statement:

  • if is a conditional statement based on condition it execute one or more statements.
  • it is also called one way selection.
          syntax:      if(expression)
                             {
                                 statement1;
                                  statement2;
                                  statement n;
                                 }

     if ...else statement:

  • it is also called two way selection statement because it select one alternative among two alternatives.
           syntax:           if(expression)
                                 {
                                  statement1;
                                  }
                                   else
                                  {
                                 statement2;
                                   }
                                  statement x;
  • if expression is true it execute statement1 and skip statement 2.then execute statement x.
  • if expression is false it skip statement1 and execute statement2 followed by statementx.

Nested if...else:

  • when  one if..else statement is included another if..else statement is called nested if...else statement.
  • it is a multyway selection statement.
syntax:
            if(exp1)
             { 
                   if(exp2)
                    statement1;
                    else
                      statement 2;
                    }else
                    statement3;
                    statement x;

Switch statement:

  • switch statement is a multi way selection statement .
  • it is similar to if ....else if statement.
syntax:           Switch(expression)
                     {
                         case value1:
                          statement1;
                          break;
                          case value2:
                           statement2;
                           break;
                             .
                            case valuen:
                            statement n;
                            break;
                             default:
                            statement d;
                            break;
                           }
                          statementx;
  • here expression is a integer value or character.

/* c program to display week day by using switch statement*/

#include<stdio.h>
#include<conio.h>
Main()
{
Int d;
Clrscr();
Printf(“Enter week day in int”);
Scanf(“%d”,&d);
Switch(d)
{
Case 1:
Printf(“Sunday”);
break;
case 2:
Printf(“monday”);
break;
case 3:
Printf(“tuesday”);
break;
case 4:
printf(“wednessday”);
break;
case 5:
Printf(“thusday”);
break;
case 6:
Printf(“friday”);
break;
case 7:
Printf(“Satday”);
break;
default:
Printf(“invalid week day”);
break;
}
getch();
}
Output:
Enter week day in int 1
sunday
 
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