SECTION A: REVIEW QUESTIONS AND EXERCISES

Q1. Write a C program to find the sum and average of three given numbers .
Ans:

#include <conio.h> // for turboc++ compilers , remove if you are not using turboc++
#include <stdio.h>


int main() {

  int num1, num2, num3, sum = 0;
  float average = 0;

  clrscr(); // remove if you are not using turboc++

  printf("Enter 3 numbers : ");
  scanf("%d %d %d", &num1, &num2, &num3);

  sum = num1 + num2 + num3;
  average = (num1 + num2 + num3) / 3.0;

  printf("Sum : %d \nAverage : %6.2f\n", sum, average);
  getch() // remove if you are not using turboc++

      return 0;
}

Q2. Write a C program to convert temperature in °C to °F using the relation °F = 1.8°C + 32.
Ans :

#include <conio.h>

int main() {
  float cel, far;

  clrscr(); // remove if not using turboc++

  printf("Enter Celsius : ");
  scanf("%f", &cel);

  far = 1.8 * cel + 32;

  printf("Farenheit : %6.2f°F\n", far);
  getch(); // remove if not using turboc++

  return 0;
}

Q3. Write a C program to find the area and circumference of a circle of radius r.
Ans :

#include <conio.h> //remove if not using turboc++
#include <stdio.h>
int main(){
    
    float r, area, circumference;
    
    clrscr(); //remove if not using turboc++
    
    printf("Enter Radius of the Circle : ");
    scanf("%f",&r);
    
    area = 22.0/7.0 * r * r; 
    circumference = 2 * 22.0/7.0 * r;
    
    printf("Area of circle : %.2f\n",area);
    printf("Circumference of Circle : %.2f\n",circumference);
    getch(); //remove if not using turboc++
    return 0;
}

Q4. Write a C program to find the value of y using the relation $y = x^2 + 2x - 1$.
Ans :

#include <conio.h> //remove if not using turboc++;
#include <stdio.h>

int main() {

  float x, y;

  clrscr(); // remove if not using tubroc++;

  printf("Enter the value of x : ");
  scanf("%f", &x);

  y = x * x + 2 * x - 1;

  printf("The value of y : %6.2f\n", y);
  
  getch(); // remove if not using turboc++;
  return 0;
}

Q5. Write a C program to find the ASCII character of a given integer.
Ans :

#include <conio.h> //remove if not using turboc++
#include <stdio.h>

int main() {

  int n;

  clrscr(); // remove if not using turboc++;

  printf("Enter number : ");
  scanf("%d", &n);

  printf("Character : %c\n",n);
             // we are converting the interger to charcter with the format
             // specifier %c which represent character ;
 
  getch();   // remove if not using turboc++;
  return 0;
}

Q6. Explain scanf() and printf() functions in C.

Ans : Printf function is used to print/display values of variables using the standard output device(monitor).It can also be use to print any character of our choice in the monitor. Whereas, Scanf function is used to read/input values of variables using the standard input device (keyboard).It is used in a program to take input from the user or where there is necessary for user interaction.

Q7. Explain the various character input/output functions in C.

Ans :

      getchat() function : It is used to read one character at a time from the standard input device(keyboard).
      putchar() function : It is ued to display one character at a time on the monitor screen.
      getch() function : It is used to read a character from the keyboard and it does not expect the enter key press.
      putch() function : It is used to display a character on the monitor.
      gets() function : It is used to read a string of characters including white space.

Q8. Mention the various conversion specifications for data I/O in C.

Ans :

int :     : %d : represents a decimal integer value 
          : %u : represents an unsigned integer value.
          : %o : represents an unsigned octal value.
          : %x : represents an unsigned hexadecimal value.

float/double :
          : %f : represents a floating point value.
          : %e : represents a floating point value in a decimal or exponential form.

char :    : %c : represents a single character value.
          : %s : represents a string of value of characters.    

Q9. Write a C program to calculate simple interest using formula $I = \frac{PNR}{100}$.
where P - Principal amount, N - Number of years, R - Rate of interest
Ans :

#include <conio.h> // remove if not using turboc++
#include <stdio.h>

int main() {

  float P, N, R, I;

  clrscr(); // remove if not using turboc++

  printf("Enter Pricipal : $ ");
  scanf("%f", &P);

  printf("Enter Time : ");
  scanf("%f", &N);

  printf("Enter Rate : ");
  scanf("%f", &R);

  I = (P * N * R) / 100.0;

  printf("Interest : $ %6.2f\n", I);
  getch(); // remove if not using turboc++
  return 0;
}

Q10. Write a C program to swap (exchange) the values of a variables A and B without using a temporary variable.
[Hint: The following assignments are used to swap the values:
A = A + B
B = A - B
A = A - B]
Ans :

#include <conio.h> // remove if not using turboc++
#include <stdio.h>

int main() {

  int A, B;

  clrscr(); // remove if not using turboc++

  printf("Enter Value of A : ");
  scanf("%d", &A);

  printf("Enter Value of B : ");
  scanf("%d", &B);

  A = A + B;
  B = A - B;
  A = A - B;

  printf("Value of A : %d\n", A);
  printf("Value of B : %d\n", B);

  getch(); // remove if not using turboc++
  return 0;
}

Q11. Earth takes a period of revolution of 31558150 seconds. Write a C program to convert this into number of days, hours and minutes.
Ans :

#include <conio.h> //remove if not using turboc++
#include <stdio.h>

int main() {

  int sec = 31558150;
  float days, hours, minutes;

  clrscr(); // remove if not using turboc++

  days = sec / 86400.0; // 1 day = 86400 seconds
  hours = sec / 3600.0; // 1 hour = 3600 seconds
  minutes = sec / 60.0; // 1 minutes = 60 seconds

  printf("Numbers of days = %.2f days\n", days);
  printf("Hours : %.2f hours\n", hours);
  printf("Minutes : %.2f minutes\n", minutes);

  getch(); // remove if not using turboc++
  return 0;
}

Q12. Write a C program to calculate the cut-off mark of a student using the formula $CM = \frac{M}{2} + \frac{P}{2} - \frac{C}{2} + E$
where CM = Cut-off mark
M = Marks in mathematics out of 200
P = Mark in Physics out of 200
C = Marks in Chemistry out of 200
E = Marks in entrance examination out of 100.
Ans :

#include <conio.h> //remove if not using turboc++
#include <stdio.h>

int main() {

  float M, P, C, E, CM;

  clrscr(); // remove if not using turboc++

  printf("Enter mark in mathematics (out of 200): ");
  scanf("%f", &M);

  printf("Enter mark in Physics (out of 200) : ");
  scanf("%f", &P);

  printf("Enter mark in Chemestry (out of 200) : ");
  scanf("%f", &C);

  printf("Enter mark in Entrance Exam (out of 100) : ");
  scanf("%f", &E);

  CM = (M / 2.0) + (P / 2.0) - (C / 2.0) + E;

  printf("Cut-Off Mark : %.2f\n", CM);

  getch(); // remove if not using turboc++
  return 0;
}

SECTION B: SHORT QUESTIONS

What is the purpose of scanf() function? How it is used within a C program?

Ans : scanf() function is used to take user input in a program. It can be used along with the format specifier and address of the variable.

What is the use of “\n”?

Ans : \n is used to move to new line in the program.

Assuming i=3, give the output for
printf("\n %d %d %d\n", i, ++i, i++);

Ans : 3 4 4

Explain the significance of the following control specifiers:

(a) %c (b) %o (c) %x (d) %d

Ans: %c : It is used to represent a single character. It can be used to take input/output of a single character.
%o : It is used to represent an unsigned octal value. It can be used to take input/output of an unsigned octal value. (octal value refers to base 8 numbers)
%x : It is used to represent an unsigned hexadecimal value. It can be used to take input/output of an unsigned hexadecimal value. (hexadecimal refers to base 16 numbers)
%d : It is used to represent a decimal integer value. It can be used to take input/output of an integer value.

What is a header file in C? List any two header files.

Ans:

The line from which a program execution begins is main().
The sign # of the compiler directive must appear at the top of a line.
Write four different C statements each adding 1 to integer variable x.

Ans : <p> The four different C statements each adding 1 to integer variable x are :
1. x = x + 1;
2. x += 1;
3. x++;
4. ++x;
</p>

How do you generate an alarm/beep using printf?

Ans : We can generate an alarm/beep using printf by using the ‘\a’ escape sequence.

What is the difference between getchar() and getche()?

Ans :

getchar()	getchare()
1. It does not display the character.	1. It display the character.
2. It expect the ‘Enter’ key to be press	2. It does not expect the ‘Enter’ key to be press.
3. It is present in the ‘stdio.h’ header file.	3. It is present in the ‘conio.h’ header file.

What is an escape sequence? What is its purpose?
Explain the need for the following:
#include <stdio.h>
#include <math.h>
Explain with examples the syntax of scanf() and printf() functions.

Ans :

What is the difference between C character and C string?
Name any four functions available in stdio.h.
The file name stdio.h is an abbreviation for ____ file.
What is the difference between 'a' and "a" in C?
How can the minimum field width for a data item be specified using the printf() function?
What are the advantages of getche() over scanf()?
Obtain the output of the following statements in C. The variables count, amt and city have the following values.
```
  int count =1275; 
  float amt =-235.74;
  char city [10] = "Chennai";
```
(a) printf("%d%f", count, amt);
(b) printf("%-10d%-15s", count, city);

Ans :

a) 1275-235.74
b) 1275 Chennai

How can precision be specified in printf function?

Ans : We can specified the precision in printf by using a formatted print with required number of decimal digits for float type varibales.

A C program contains the following variable declaration: int i = 12345, j = 0xbcd9, k077777; What will be the output of the printf() function?

Ans : i = 12345,
j = 0xbcd9 = 48345 (converting hexadecimal to decimal value, the number starting with 0x is in form of hexadecimal. )
k = 077777 = 32767 (converting octal to decimal value, the number starting with 0 is in form of octal.)