In the term software or computer programming, it has a set of instructions (in simple or complex form) called a program. These instructions are also called statements, which occur sequentially or in either a conditional way or in an iterative way. To handle such types of statements some flow controls are required. These flow controls are called Control Statements.
The control flow statements of a language specify the order in which computations are performed. They determine the “Flow of Control” in a program. C programming language provides two types of control statements.
- Selection or Decision Control Statements: The decision and case control statements allow selective processing of a statement of a group of statements. These are also called as Conditional Statements.
- Repetition or Loop Control Statements: The Loop control statement executes a group of statements repeatedly till a condition is satisfied.
In other words, the control statements are used to control the cursor in a program according to the condition or according to the requirement in a loop. There are mainly three types of control statements or flow controls. These are illustrated as below:
- Branching
- Looping
- Jumping
Branching
if statement
The if statement is a powerful decision-making statement that can handle a single condition or group of statements. These have either true or false actions. When only one condition occurs in a statement, then a simple if statement is used having one block.
/*Any Number is input through the keyboard. write a If program.*/
#include <stdio.h>
#include <conio.h>
void main()
{
int n;
n=1;
clrscr(); //clrscr() is the function of #include< conio.h > header file which will clear previous output of program
printf("Enter the Number");
scanf("%d",&n);
if(n>0)
{
printf("It is If Statement");
}
getch();
}
if-else statement
This statement also has a single condition with two different blocks. One is true block and other is false block.
/*Any Number is input through the keyboard. write a program to find out whether It is an Odd Number or Even Number.*/
#include <stdio.h>
#include <conio.h>
void main()
{
int n;
n=1;
clrscr();
printf("Enter the Number");
scanf("%d",&n);
if(n%2==0)
{
printf("This is Even Number");
}
else
{
printf("This is Odd Number");
}
getch();
}
Output is as follows:
Enter the Number 4 This is Even Number
nested if statement
When an if statement occurs within another if statement, then such type is called nested if statement.
/*If the ages of Ram, sham, and Ajay are input through the keyboard, write a program to determine the youngest of the three*/
#include <stdio.h>
#include <conio.h>
void main()
{
int ram,sham,ajay;
clrscr();
printf("Enter the Three Ages of Ram,Sham and Ajay\n");
scanf("%d%d%d",&ram,&sham,&ajay);
if(ram < sham)
{
if(ram < ajay)
{
printf("Ram is Youngest");
}
else
{
printf("Ajay is Youngest");
}
}
else
{
if(sham < ajay)
{
printf("Sham is Youngest");
}
else
{
printf("Ajay is Youngest");
}
}
getch();
}
Output is as follows:
Enter the three Ages of Ram,Sham and Ajay 14 17 19 Ram is Youngest
Ladder if or else if statement
When in a complex problem, number of conditions arise in a sequence, then we can use Ladder-if or else if statement to solve the problem in a simple manner.
The marks obtained by a student in 5 different subjects are input through the keyboard. The student gets a division as per the following rules:
=> Percentage above or equal to 60 - First Division
=> Percentage between 50 and 59 - Second Division
=> Percentage between 40 and 49 - Third Division
=> Percentage less than 40 - Fail
Method 1
/*Write a program to calculate the division obtained by the student. There are two ways in which we can write a program for this example. These methods are given below: */
//Method-1
#include< stdio.h >
#include< conio.h >
void main()
{
int eng,math,com,sci,ss,total;
float per;
clrscr();
printf("Enter Five Subjects Marks\n");
scanf("%d%d%d%d%d",&eng,&math,&com,&sci,&ss);
total = eng + math + com + sci + ss ;
printf("Toal Marks : %d",total);
per = total * 100.00 / 500;
printf("\n Percentage : %f", per);
if(per >= 60)
{
printf("\n 1st Division");
}
else if(per >= 50)
{
printf("\n 2nd Division");
}
else if(per >= 40)
{
printf("\n 3rd Division");
}
else
{
printf("\n Sorry Fail");
}
getch();
}
Method 2
//Method-2
#include< stdio.h >
#include< conio.h >
void main()
{
int eng,math,com,sci,ss,total;
float per;
clrscr();
printf("Enter Five Subjects Marks\n");
scanf("%d%d%d%d%d",&eng,&math,&com,&sci,&ss);
total = eng + math + com + sci + ss ;
printf("Toal Marks : %d",total);
per = total * 100.00 / 500;
printf("\n Percentage : %f", per);
if(per >= 60)
{
printf("\n 1st Division");
}
if(per >= 50 && per < 60)
{
printf("\n 2nd Division");
}
if(per >= 40 && per < 50)
{
printf("\n 3rd Division");
}
if(per < 40)
{
printf("\n Sorry Fail");
}
getch();
}
switch statement
When a number of conditions (multiple conditions) occurs in a problem and it is very difficult to solve such type of complex problem with the help of a ladder if statement, then there is a need for such type of statement which should have different alternatives or different cases to solve the problem in a simple and easy way. For this purpose switch statement is used.
/*WAP to print the four-days of week from monday to thrusday which works upon the choice as S,M,T,H using switch case*/
#include <stdio.h>
#include <conio.h>
void main()
{
char n;
clrscr();
printf("Enter the Choice from Four Days...\n")
printf("S = Sunday \n")
printf("M = Monday \n")
printf("T = Tuesday \n")
printf("H = Thursday \n\n")
scanf("%c",&n);
switch(n)
{
case 'S':
printf("Sunday");
break;
case 'M':
printf("Monday");
break;
case 'T':
printf("Tuesday");
break;
case 'H':
printf("Thursday");
break;
default:
printf("Out of Choice");
break;
}
getch();
}
Output is as follows:
Enter the Choice from Four Days... S = Sunday M = Monday T = Tuesday H = Thursday S Sunday
Conditional Control Statement
This statement is based on a conditional operator. This statement solves the problem's condition in a single line and is a fast executable operation. For this purpose, we can take a combination of ? and :
/*The easiest way to use conditional control statement*/
#include <stdio.h>
#include <conio.h>
void main()
{
int n;
clrscr();
n%4==0 ? printf("Leap Year") : printf("Not Leap Year");
//OR
//printf(n%4==0 ? "Leap Year" : "Not Leap Year");
getch();
}