C Decision control statement
Decision Making
C conditional statements are used to specify one or more conditions. The statements will be executed if the condition becomes true otherwise alternative statement will be executed if the condition becomes false. C language supports the following statement:- If statement
- Switch Statement
- Conditional operator statement
- goto statement
If statement is used to perform the operation according to condition. In other words, we can say that it controls the flow of execution of the statement. The condition may be true or false.
There are various ways to use if statement:
- If statement
- If-else statement
- Else if Ladder
In C language, if statement is used to execute the code if the condition is true.
The following syntax of if statement is:
Syntax:
if(expression/ condition)
{
//code to be executed
}
Example
#include <stdio.h>
int main()
{
int n=0;
printf("---- To Chcek The Number is Even or Odd ---- \n");
printf("Enter any number : ");
scanf("%d",&n);
if(n%2==0){
printf("Even Number");
}
return 0;
}
Output
---- To Chcek The Number is Even or Odd ---- Enter any number : Even Number
If- else statement:
If-else statement is used to execute the code if the condition is true or false. The given following
Syntax of if-else statement:
if(expression)
{
//code to be executed if condition is true
}else{
//code to be executed if condition is false
}
Example
#include <stdio.h>
int main()
{
int n=0;
printf("---- To Chcek The Number is Even or Odd ---- \n");
printf("Enter any number : ");
scanf("%d",&n);
if(n%2==0){
printf("Even Number");
}
else{
printf("Odd Number");
}
return 0;
}
Output
---- To Chcek The Number is Even or Odd ---- Enter any number : Even Number
If else-if ladder statement
It is used to execute one code from multiple conditions.
Syntax:
if(expression1)
{
statement block1;
}
else if(expression2)
{
statement block2;
}
else if(expression3 )
{
statement block3;
}
Else
default statement;
Switch Statement
The switch statement is used to execute the code from multiple condition or case. Following is the flow chart of the switch statement.
Syntax:
switch(expression)
{
case value-1:
block-1;
break;
case value-2:
block-2;
break;
case value-3:
block-3;
break;
case value-4:
block-4;
break;
default:
default-block;
break;
}
Rules for switch statement
The switch(expression) must be an integer or character type.
- We can use only byte, short, int, char data type with a switch statement.
- With switch statement not use float data type.
- We can use any number of case statements within a switch.
- The case value can be used only inside the switch statement.
- Value for a case must be the same as the variable in a switch.
#include <stdio.h>
#include <stdlib.h>
int main()
{
int ch;
printf("Enter any Number: ");
scanf("%d",&ch);
switch(ch)
{
case 1:
printf("Today is Sunday");
break;
case 2:
printf("Today is Monday");
break;
case 3:
printf("Today is Tuesday");
break;
case 4:
printf("Today is Wednesday");
break;
case 5:
printf("Today is Thursday");
break;
case 6:
printf("Today is Friday");
break;
case 7:
printf("Today is saturday");
break;
default:
printf("Please Enter Value between 1 to 7");
return 0;
}
}
Output
Enter any Number: Please Enter Value between 1 to 7Example
#include <stdio.h>
int main()
{
int day;
printf("Enter any Week day Number: ");
scanf("%d",&day);
if(day==1){
printf("1st day Sunday");
}
else if(day==2){
printf("2nd Day Monday");
}
else if(day==3){
printf("3rd Day Tuesday");
}
else if(day==4){
printf("4th Day Wednersday ");
}
else if(day==5){
printf("5th Day Thursday");
}
else if(day==6){
printf("6th Day Friday");
}
else if(day==7){
printf("7th Day Saurday");
}
else{
printf("Not a Day of Week");
}
return 0;
}
Output
Enter any Week day Number: Not a Day of Week