undefined | unit 2 input and output operations

C PPS

UNIT 2INPUT OUTPUT OPERATIONS Q1)What is input output operations?A1)Single character input output:The basic operation done in input output is to read a characters from the standard input device such as the keyboard and to output or writing it to the output unit usually the screen. The getchar function can be used to read a character from the standard input device. The scanf can also be used to achieve the function. The getchar has the following form.Variable name = getchar:Variable name is a valid ‘C’ variable, that has been declared already and that possess the type char.Example:

# include < stdio.h > // assigns stdio-h header file to your program

void main ( ) // Indicates the starting point of the program.

{

char C, // variable declaration

printf (“Type one character:”) ; // message to user

C = getchar () ; // get a character from key board and

Stores it in variable C.

Printf (” The character you typed is = %c”, C) ; // output

} // Statement which displays value of C on

// Standard screen.

Program shows the use of getchar function in an interactive environment.

#include < stdio.h > // Inserts stdio.h header file into the Pgm

void main ( ) // Beginning of main function.

{

char in; // character declaration of variable in.

printf (” please enter one character”); // message to user

in = getchar ( ) ; // assign the keyboard input value to in.

putchar (in); // out put ‘in’ value to standard screen.

}

String input and output:The gets function relieves the string from standard input device while put S outputs the string to the standard output device. A strong is an array or set of characters.The function gets accepts the name of the string as a parameter, and fills the string with characters that are input from the keyboard till newline character is encountered. (That is till we press the enter key). All the end function gets appends a null terminator as must be done to any string and returns.The puts function displays the contents stored in its parameter on the standard screen.The standard form of the gets function is gets (str)Here "str" is a string variable.Q2) Explain conditional branching?A2)

if Statements

This statement permits the programmer to allocate condition on the execution of a statement. If the evaluated condition found to be true, the single statement following the "if" is execute. If the condition is found to be false, the following statement is skipped. Syntax of the if statement is as follows

if (condition)

statement1;

statement2;

In the above syntax, “if” is the keyword and condition in parentheses must evaluate to true or false. If the condition is satisfied (true) then compiler will execute statement1 and then statement2. If the condition is not satisfied (false) then compiler will skip statement1 and directly execute statement2. Syntax of the “if----else” statement is as follows

if (condition)

statement1;

else

statement2;

In the above syntax, “if” and “else” are the keywords and condition in parentheses must evaluate to true or false. If the condition is satisfied (true) then compiler will execute statement1 and skip statement2. If the condition is not satisfied (false) then compiler will skip statement1 and directly execute statement2. Nested if-----else statements :Nested “if-----else” statements are used when programmer wants to check multiple conditions. Nested “if---else” contains several “if---else” a statement out of which only one statement is executed. Number of “if----else” statements is equal to the number of conditions to be checked. Following is the syntax for nested “if---else” statements for three conditions

if (condition1)

statement1;

else if (condition2)

statement2;

else if (condition3)

statement3;

else

statement4;

In the above syntax, compiler first check condition1, if it trues then it will execute statement1 and skip all the remaining statements. If condition1 is false then compiler directly checks condition2, if it is true then compiler execute statement2 and skip all the remaining statements. If condition2 is also false then compiler directly checks condition3, if it is true then compiler execute statement3 otherwise it will execute statement 4.

Switch Statements

This statement permits the programmer to choose one option out of several options depending on one condition. When the “switch” statement is executed, the expression in the switch statement is evaluated and the control is transferred directly to the group of statements whose “case” label value matches with the value of the expression. Syntax for switch statement is as follows:

switch(expression)

{

case constant1:

statements 1;

break;

case constant2:

statements 2;

break;

…………………..

default:

statements n;

break;

}

Q3)Write a program to check whether the number is even or odd.A3)

#include <stdio.h>

int main() {

int number;

printf("Enter an integer: ");

scanf("%d", &number);

// True if the remainder is 0

if (number%2 == 0) {

printf("%d is an even integer.",number);

}

else {

printf("%d is an odd integer.",number);

}

return 0;

}

Q4) Explain loop statements?A4)Iteration statements create loops in the program. In other words, it repeats the set of statements until the condition for termination is met. Iteration statements in C are for, while and do-while.while statement:The while loop in C is most fundamental loop statement. It repeats a statement or block while its controlling expression is true.The general form is:while(condition) { // body of loop }The condition can be any boolean expression. The body of the loop will be executed if the conditional expression is true.Here is more practical example.The output of the program is:tick 10 tick 9 tick 8 tick 7 tick 6 tick 5 tick 4 tick 3 tick 2 tick 1do-while statementThe do-while loop always executes its body at least once, because its conditional expression is at the bottom of the loop. Its general form is:do{ // body of loop} while(condition);Each iteration of the do-while loop first executes the body of the loop and then evaluates the conditional expression. If this expression is true, the loop will repeat. Otherwise, the loop terminates. As with all of C’s loops, condition must be a Boolean expression.

for loop

Here is the general form of the traditional for statement:

for(initialization; condition; iteration) {

// body

}

Q5) Write a program to find the sum of n numbers?A5)

#include <stdio.h>

int main()

{

int n, count, sum = 0;

printf("Enter the value of n(positive integer): ");

scanf("%d",&n);

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

{

sum = sum + count;

}

printf("Sum of first %d natural numbers is: %d",n, sum);

return 0;

}

Output:

Enter the value of n(positive integer): 6

Sum of first 6 natural numbers is: 21 Q6) Write a program to find the roots of the quadratic equation?A6)

#include <math.h> #include <stdio.h> int main() { double a, b, c, discriminant, root1, root2, realPart, imagPart; printf("Enter coefficients a, b and c: ");
		scanf("%lf %lf %lf", &a, &b, &c); discriminant = b * b - 4 * a * c; // condition for real and different roots if (discriminant > 0) { root1 = (-b + sqrt(discriminant)) / (2 * a); root2 = (-b - sqrt(discriminant)) / (2 * a); printf("root1 = %.2lf and root2 = %.2lf", root1, root2); } // condition for real and equal roots else if (discriminant == 0) { root1 = root2 = -b / (2 * a); printf("root1 = root2 = %.2lf;", root1); } // if roots are not real else { realPart = -b / (2 * a); imagPart = sqrt(-discriminant) / (2 * a); printf("root1 = %.2lf+%.2lfi and root2 = %.2f-%.2fi", realPart, imagPart, realPart, imagPart); }
	return 0; } Enter coefficients a, b and c: 2.3 4 5.6
	root1 = -0.87+1.30i and root2 = -0.87-1.30i

Q7) Write a program to find binomial co-effecients?A7)

#include <stdio.h>

// Function for binomial coefficient table

int bin_table(int val) {

for (int i = 0; i <= val; i++) {

printf("%2d", i);

int num = 1;

for (int j = 0; j <= i; j++) {

if (i != 0 && j != 0)

num = num * (i - j + 1) / j;

printf("%4d", num);

}

printf("\n");

}

int main() {

int value = 5;

bin_table(value);

return 0;

}

Q8) Write a program to find Pascal’s triangle ?A8)

#include <stdio.h>

int main() {

int rows, i, j, space;

printf("Enter the number of rows: ");

scanf("%d", &rows);

for (i = rows; i >= 1; --i) {

for (space = 0; space < rows - i; ++space)

printf(" ");

for (j = i; j <= 2 * i - 1; ++j)

printf("* ");

for (j = 0; j < i - 1; ++j)

printf("* ");

printf("\n");

}

return 0;

}

1 1

1 2 1

1 3 3 1

1 4 6 4 1

1 5 10 10 5 1

Q9) Write a program to print even numbers less than 10.A9)

	#include<stdio.h> #include<conio.h>
int main() { int num=1; //initializing the variable do //do-while loop { printf("%d\n",2*num); num++; //incrementing operation }while(num<=10); return 0; } Output: 2 4 6 8 10 12 14 16 18
20