If ……….else statement:
The if..else statement is a two way branch: it means do one thing or the other. When it is executed, the condition is evaluated and if it has the value `true' (i.e. not zero) then statement1 is executed. If the condition is `false' (or zero) then statement2 is executed. The if..else construction often saves an unnecessary test from having to be made.
if (condition)
{
statements
}
else
{
statements
}
Example:
/*-------------------------------------------------------*/
/* To find whether a given year is leap or not */
/*-------------------------------------------------------*/
main()
{
int y, r1, r2;
printf("Enter a year");
scanf("% d", &y);
r1 = y % 4;
if (r1 = = 0)
{
r2 = y % 100;
if (r2 = = 0)
printf("The given year is not a leap year");
else
printf("The given year is a leap year");
}
else
printf("The given year is not a leap year");
}
Logical Operators:
Comparisons are often made in pairs or even in groups and linked together with words like OR and AND. The following are the logical operators in C:
- || [logical OR]
- & & [logical AND]
- ! [logical NOT]
[ || ]OR Logical Operator
Condition-I Condition-II Result ----------- ----------- --------- True False True False True True False False False True True True
[& &]AND Logical Operator
Condition-I Condition-II Result ---------- ------------ --------- True False False False True False False False False True True True
[!] NOT Logical Operator
!(True) => False
!(false) => True
Example:
/*--------------------------------------------------------------------------------------------*/
/* To check whether a given alphabet is capital or not (using logical operator) */
/*--------------------------------------------------------------------------------------------*/
main()
{
char x;
printf("Enter an alphabet");
scanf("%c", &x);
if (x >= 65 && x <= 90)
printf("The given alphabet is capital");
else
printf("The given alphabet is not capital");
}
Switch Statement:
The switch statement is another way of making a program path branch into lots of different limbs. The switch statement has the following form:
switch (integer value or constant value)
{
case 1: statement1;
break; /* optional line */
case 2: statement2;
break; /* optional line */
....
default: default statement
break; /* optional line */
}
Example:
/* Input a direction code and print the direction name(using switch)*/
main()
{
char y;
clrscr();
printf("Enter the code");
scanf("%c", &y);
switch (y)
{
case 'N':
printf("North Direction");
break;
case 'S':
printf("South Direction");
break;
case 'E':
printf("East Direction");
break;
default:
printf("West Direction");
break;
}
}