C PROGRAMING: A Beginner’s Course | CHAPTER 4 Control Statements

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CHAPTER 1   Introduction and structure of C program

CHAPTER 2   Data types, Constants, Variables and I/O Statements

CHAPTER 3   Operators and Expressions

CHAPTER 4   Control Statements

CHAPTER 5   Arrays

CHAPTER 6   String Manipulations

CHAPTER 7   Functions

CHAPTER 8   Structure, Unions and Enumerated Data types  

CHAPTER 9   Pointers

CHAPTER 4

CONTROL STATEMENTS

            In C, usually the control flows from one instruction to the next instruction. This control flow from one command to the next is called sequential control flow. But,  in most C programs the programmer may want to skip instructions or repeat a set of instructions repeatedly when writing logic. This can be referred to as sequential control flow. The declarations in C let programmers make such decisions which are called decision-making or control declarations.

There are four types of control statements in C:

·       Conditional/Decision making statements

·       Selection/Switch statement

·       Iteration statements

·       Unconditional/Jump statements

·       CONDITIONAL/DECISION MAKING

The if, if-else, nested if-else statements are used to carry out a logical test and then take one of two possible actions depending on the outcome of the test (ie, whether the outcome is true or false).

v If

Syntax:-

if(condtion is true)

{

True statements;

}

Ex:-

 main()

{

int i;

printf(“enter the number<10”);

scanf(“%d”,&i);

if(i<10)

printf(“the entered number is %d<10”, i);

}         

             

v If-Else

Syntax:-

if(condtion )

{

True statements;

                                                }

else

{         

False statement;

}

Ex:-

 main()

{

int i;

printf(“enter the number<10”);

scanf(“%d”,&i);

 

if(i<10)

printf(the entered number is less than 10”);

else

printf(the entered number is greater than 10”);

}

v Nested if

Syntax:-

if(condition 1)

{

                        if(condtion 2)

                          {

                                     True statements2;

                         }

                         else

                         {

                                     False statement 2;

                         }

}

else

{

False statement 1;   }

Ex:- main()

{

int i;

printf(“enter the number”);

scanf(“%d”,&i);

if(i<10)

printf(the entered number is less than 10”);

else{

if(i==10)

printf(the entered number is equal to 10”);

else

printf(the entered number is greater than 10”);

                                          }

                                   }

·       SELECTION/SWITCH

A switch statement is used for multiple way selections that will branch into different code segments based on the value of a variable or expression. This expression or variable must be of integer data type.

switch(expression)

{

case constant 1:

      Block;

break;

case constant 2:

      Block;

 break;

.

.

.

default:

default block;

}

Ex:

 main()

{

int a=1;

switch(a)

{

case 1:

printf(“ I am 1\n”);

break;

case 2:

printf(“ I am 2\n”);

break;

default:

printf(“ I am 3\n”);

}

}

·       ITERATION

Iteration provide a way to repeat commands and control how many times they are repeated

v for

Syntax:-

for(initialize counter; test condition; increment/decrement counter)

{

Body of the loop;

….

}

Ex:-

int i,n, sum;

for(i=1;i<=10;i++)

{

  printf(“enter any number”)

scanf(“%d”,&i);

if(n<0)

continue;

}

 

v While

 Syntax:-

 while(condition)

  {

    …………..

    Body of the condition

    ………….

}

 Ex :-

 int i, j;

 i=1;

while(i<0)

{

                   j-1;

                   i++;

}

printf(“ enter the max value is %d”,j);

printf(“the value after the overflow is %d”,i);

}

v Do while

Syntax :

Do

{

 …………………..

Body of the condition;

…….……………

}while(condition);

Example:-

 main()

{

int i, n;

printf(“enter the number:”);

scanf(“%d”,&n);

i=0;

do

{

printf(“the number is %d”n);

i=i+1;

}while(i<n);

}

 ·       UNCONDITIONAL/JUMP

v    Break;

1. It is used to come out of the loop instantly. When a break statement is encountered inside a loop, the control directly comes out of loop and the loop gets terminated. It is used with if statement, whenever used inside loop.
2. This can also be used in switch case control structure. Whenever it is encountered in switch-case block, the control comes out of the switch-case.

Syntax:-

break;

Ex:-

main()

{

int i;

for(i=1;i<=10;i++)

 {

if(i==6)

break;

               printf(“%d”,i);

}

}

v Continue

The continue statement is used inside loops. When a continue statement is encountered inside a loop, control jumps to the beginning of the loop for next iteration, skipping the execution of statements inside the body of loop for the current iteration.

Syntax:

Continue;

Ex:-int i,n, sum;

 for(i=1;i<=10;i++)

{

printf(“enter any number”)

scanf(“%d”,&i);

if(n<0)

continue;

                                                       else

sum=sum+n;

}

Printf(“sum is ….%d”,sum);

}

v Goto

The goto statement is rarely used because it makes program confusing, less readable and complex. Also, when this is used, the control of the program won’t be easy to trace, hence it makes testing and debugging difficult.

Syntax:

goto label;

……….

……..

Label:

Ex:-

 main()

{

int a,b;

printf(“\n enter the two numbers”);

scanf(“%d%d”,&a,b);

if(a==b)

goto equal;

else{

Printf(“\n a and b or not equal”);

exit(0);

}

equal:

printf(“a and  b are equal”);

}                                                                                                                                   EXAMPLE PROGRAMS:

1.     Write a program to find biggest number.

#include<stdio.h>

#include<conio.h>

void main()

{

int a,b;

clrscr();

printf("Enter the two nos.:");

scanf("%d%d",&a,&b);

      if(a>b)

      {

                  printf("A is big");

      }

getch();

}

2.     Write a program to check the given two numbers are equal or not

#include<stdio.h>

#include<conio.h>

void main()

{

int a,b;

clrscr();

printf("Enter any two values:");

scanf("%d%d",&a,&b);

      if(a==b)

      {

      printf("A & B both are equal");

      }

      else

      {

      printf("Not equal");

      }

getch();

}

3.     Write a program to find biggest number among three numbers.

#include<stdio.h>

#include<conio.h>

void main()

{

int a,b,c;

clrscr();

printf("Enter any three nos.:");

scanf("%d%d%d",&a,&b,&c);

      if((a>b)&&(a>c))

      {

      printf("A is big");

      }

      else

      {

                  if(b>c)

                  {

                  printf("B is big");

                  }

                  else

                  {

                  printf("C is big");

                  }

      }

getch();

}

4.     Example program for if-else condition.

#include<stdio.h>

#include<conio.h>

void main()

{

int a;

clrscr();

printf("Enter the no.(1-4):");

scanf("%d",&a);

      if(a==1)

                  printf("One");

      else if(a==2)

                  printf("Two");

      else if(a==3)

                  printf("Three");

      else if(a==4)

                  printf("Four");

      else

                  printf("Invalid entry");

getch();

}

 

5.     Example program for switch condition.

#include<stdio.h>

#include<conio.h>

void main()

{

int a;

clrscr();

printf("Enter the no.(1-4):");

scanf("%d",&a);

      switch(a)

      {

                  case 1:

                              printf("One");

                              break;

                  case 2:

                              printf("Two");

                              break;

                  case 3:

                              printf("Three");

                              break;

                  case 4:

                              printf("Four");

                              break;

                  default:

                              printf("Invalid entry");

      }

getch();

}

6.     Write a program to find factorial of a number.

#include<stdio.h>

#include<conio.h>

void main()

{

int n,i,f;

clrscr();

printf("Enter the no.:");

scanf("%d",&n);

f=1;i=1;

      while(i<=n)

      {

      f=f*i;

      i++;

      }

printf("The factorial value of %d is %d",n,f);

getch();

}

7.     Write a program to display multiplication table for given number.

#include<stdio.h>

#include<conio.h>

void main()

{

int i,j,k;

clrscr();

printf("Enter the value for i:");

scanf("%d",&i);

j=1;

do

{

k=i*j;

printf("%d x %d = %d\n",i,j,k);

j++;

}while(j<=12);

getch();

}

8.     Write a program to print fibonacci series.

#include<stdio.h>

#include<conio.h>

void main()

{

int f1,f2,f3,n,i;

clrscr();

printf("Enter the no.of lines:");

scanf("%d",&n);

f1=1;f2=1;

printf("%d\n%d\n",f1,f2);

for(i=3;i<=n;i++)

{

f3=f1+f2;

f1=f2;

f2=f3;

printf("%d\n",f3);

}

getch();

}

9.     Example program for goto condition.

#include<stdio.h>

#include<conio.h>

void main()

{

int a,b,c;

clrscr();

printf("Enter the a,b values:");

scanf("%d%d",&a,&b);

c=a+b;

printf("The addition of c is %d",c);

goto l1;

printf("The increment value of c is %d",++c);

l1:getch();

}

10.  Example program for continue condition.

#include<stdio.h>

#include<conio.h>

void main()

{

int n,n1;

clrscr();

printf("Enter the no.:");

scanf("%d",&n1);

      for(n=10;n>0;n--)

      {

                  if(n==n1)

                              continue;

      printf("%d\n",n);

      }

getch();

}

11.  Example program for break condition.

#include<stdio.h>

#include<conio.h>

void main()

{

int n,n1;

clrscr();

printf("Enter the no.:");

scanf("%d",&n1);

      for(n=10;n>0;n--)

      {

                  if(n==n1)

                  {

                              printf("Countdown aborted");

                              break;

                  }

      printf("%d\n",n);

      }

getch();

}

12.  Write a program to check given number is even or odd.

#include<stdio.h>

#include<conio.h>

void main()

{

Int  n;

clrscr();

printf("Enter the no.:");

scanf("%d",&n);

      n=n%2;

      if((n==0))

                  printf("Even");

      else

                  printf("Odd");

getch();

}

13.  Write a program to check given is leap year or not.

#include<stdio.h>

#include<conio.h>

void main()

{

int year;

clrscr();

printf("Enter the year:");

scanf("%d",&year);

      year=year%4;

      if(year==0)

      printf("Leap year");

      else

      printf("Not leap year");

getch();

}

14.  Example program for For-loop condition.

#include<stdio.h>

#include<conio.h>

void main()

{

int i,n;

clrscr();

printf("Enter the no.:");

scanf("%d",&n);

      for(i=1;i<=n;i++)

                  printf("%d\n",i);

getch();

}

15.  Example program for nested For-loop condition.

#include<stdio.h>

#include<conio.h>

void main()

{

int i,j,n;

clrscr();

printf("Enter the no.:");

scanf("%d",&n);

for(i=1;i<=n;i++)

{

for(j=1;j<=i;j++)

{

printf("%d\t",j);

}

printf("\n");

}

getch();

}




TN 10TH SAMACHEER MATHS EXERCISE 2.5 SOLUTIONS

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