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1 Test Paper 1 Programming Language 1(a) What is a variable and value of a variable? A variable is an identifier and declared in a program which hold a value defined by its type e.g. integer, character etc. Here a variable is declared named x which holds integer type value as well as value 3 is assigned. int x; x=3; (b) Describe four basic data types. Write the purpose of the qualifiers const and volatile. The four basic data types are: (i) Integer (ii) Real (iii) Character and (iv) String. These are defined using the keyword int, float and char respectively. const: Makes variable value or pointer parameter unmodifiable. When const is used with a variable, it uses the following syntax: const variable-name [ = value]; In this case, the const modifier allows you to assign an initial value to a variable that cannot later be changed by the program. For example, const my_age = 32; Any assignments to 'my_age' will result in a compiler error. However, such declaration is quite different than using #define my_age 32 In the first case, the compiler allocates a memory for 'my_age' and stores the initial value 32 there, but it will not allow any later assignment to this variable. But, in the second case, all occurences of 'my_age' are simply replaced with 32 by the preprocessor, and no memory will be allocated for it. Warning: a const variable can be indirectly modified by a pointer, as in the following example: *(int*)&my_age = 35; When the const modifier is used with a pointer parameter in a function's parameter list, it uses the following syntax: function-name (const type *var-name)

2 Then, the function cannot modify the variable that the pointer points to. For example, int printf (const char *format,...); Here the printf function is prevented from modifying the format string. Volatile: If we declare a variable as volatile, every time the fresh value is updated. The volatile keyword can be used to state that a variable may be changed by hardware, the kernel, another thread etc. The volatile keyword may prevent unsafe compiler optimisations for memory-mapped input/output. (c) Which of the following are invalid variable names and why; (i) doubles; (ii) Minimum; (iii) row total; (iv) 3rd-row; (v) name. (iii) row and total is separated by white space which makes it invalid variable name. The correct name is row_total. (iv) 3rd-row is wrong variable name. Because digit should not be the first character and hyphen is now allowed in any identifier. The correct name is third_row. (d) Write a program in C to calculate the area and circumference of a circle. #include <conio.h> #define PI void main() float radius, circumference, area; clrscr(); printf( Enter value of Radius ); scanf( %f,&radius); area=pi*radius*radius; circumference=2*pi*radius; printf( \nthe circle area = %f and circumference = %f, area, circumference);

3 2(a) What are the different types of operators used in C program? With example and explain about logical operators and bitwise operators. The operator used in C programming language are : (i) Arithmetic operator/unary Operator & Assignment Operator (ii) Relational Operator (iii) Logical Operator (iv) Bitwise operator Arithmetic/Unary operator: +, _ Assignment Operator: = Relational Operator: <, >, <=, >= Logical Operator: &&,, == Bitwise Operator: Example: x=3; x=x+1; Here 3 is assigned in x in the first expression and x s value in incremented using arithmetic/unary operator (+) and again assigned in x in the next statement. x=8; y=5; if((x*y)>30) printf( %d,(x*y)); Here the multiplication result of (x*y) is compared with 30 using relational operator greater than (>) and if it is greater than 30 then it is shown on the display screen. char ch1,ch2; if((ch1== a ) (ch2== A ))printf( Same alphabet ); In this above example, either ch1 or ch2 holds small a or capital A, then a text message is displayed. is logical OR used in this example. (b) Why we need to use #include <math.h> and #include <ctype.h> statement in C program? math.h is header file which is included in a C program when some mathematical functions are used in the program e.g. sqrt(x); returns value of square root of x. This particular function is only found in math.h header file. ctype.h is another header file which is included in a C program when character related functions are used in that program e.g. tolower(); or tupper(); which functions returns a character into upper case and lower case respectively. These functions are used for character case conversion.

4 (c) In what ways does a switch statement differ from an if statement? An example of if statement is if(x==5)printf( Five ); This above example is simple but it can be nested as follows: if (x==0) printf( Zero ); else if (x==1) printf( One ); else if (x==2) printf( Two ); else if (x=3) printf( Three ); else printf( More than 3 ); This above statement can also be written using switch statement as follows: switch(x) case 0: printf( Zero ); break; case 1: printf( One ); break; case 2: printf( Two ); break; case 3: printf( Three ); break; default: printf( More than 3 ); break; Therefore, a switch statement is differed from nested if else statement in above manner. (d) Write down the general form and flowchart of IF, IF-ELSE and nested IF-ELSE statement. The general form of IF statement: if (condition)expression IF-ELSE statement: if (condition)expression 1 elseexpression 2 nested IF-ELSE statement: if (condition)expression 1 else if (condition)expression 2 else if (condition)expression 3 else expression 4

5 Flowcharts: cond cond expr expr2 expr1 IF statement IF-ELSE statement cond cond expr1 cond expr2 expr3 expr4 Nested IF-ELSE statement (e) Write a C program to find the number of and sum of all integers greater than 50 and less than 300 that are divisible by 9? #include <conio.h> void main() int generate_number(int x);//function prototype int summation(int x[],int n);//function prototype int i,index,sum,temp; int values[100]; clrscr(); index=0; for(i=51;i<=300;i++) temp=generate_number(i); if(temp!=0) values[index]=temp;

6 index++; printf("\n"); sum=summation(values,index); printf("\n"); printf("sum = %d",sum); getche(); int generate_number(int x) if((x%9)==0) printf("%d, ",x); return(x); else return 0; int summation(int x[],int n) int s,i; s=0; printf("\n"); for(i=0;i<n;i++) s=s+x[i]; return(s); 3(a) Is it a good approach to use goto statement? Explain your opinion. Let us have an iterative example. We want to find out sum of first 10 natural integers. A program segment is written below. sum=0; count=1; e1: sum=sum+count; count=count+1; if(count<=10) goto e1;

7 In this above sum and count are assigned 0 and 1 initially in the first two statements. The third statement sum=sum+count is preceded by e1. Here e1 is a label of that statement. The value of count in incremented by 1 in the immediate next statement and in the last statement value of count is checked. If the value is below or equal to 10 then using goto statement the control jumps from last statement to third statement and the process is iterated repeatedly until the value of count exceeds 10. This above program segment can easily be written using control structure. Using for loop, we can write, sum=0; for(count=1;count<=10;count++) sum=sum+count; This above control structure implementation is simpler and more professional. Therefore I believe that usage of goto statement should be avoided. (b) In what ways does switch-break statement differ from if-else if-else statement? An example of if statement is if(x==5)printf( Five ); This above example is simple but it can be nested as follows: if (x==0) printf( Zero ); else if (x==1) printf( One ); else if (x==2) printf( Two ); else if (x=3) printf( Three ); else printf( More than 3 ); This above statement can also be written using switch statement as follows: switch(x) case 0: printf( Zero ); break; case 1: printf( One ); break; case 2: printf( Two ); break; case 3: printf( Three ); break; default: printf( More than 3 ); break;

8 Therefore, a switch statement is differed from nested if else statement in above manner. (c) Write a program in C to determine whether a number is a prime or not. #include <conio.h> void main() int num, rem; clrscr(); printf( Enter a positive integer value: ); scanf( %d,&num); if((num==1) (num==2) (num==3))printf( The number is prime ); else rem=num%2; if(rem!=0) printf( The number is not prime ); getche(); (d) The number in a sequence are called Fibonacci numbers. Write a C program using for loop to calculate and print the first 20 Fibonacci number. #include <conio.h> void main() int f1, f2, f3, i; f1=1; f2=1; clrscr(); printf( %d,f1); printf( %d,f2); for(i=3;i<=20;i++) f3=f2+f1; printf( %d,f3); f1=f2; f2=f3;

9 getche(); 4(a) What is an array? Define a two-dimensional integer array and input data values of 4 rows and 5 columns each. An array is a series of objects where all the objects are of same type. The general form of declaration of array is <storage class> <data type> array_name[expression]; For example, an array named x is declared with the size of 10 objects of all integer types int x[10]; A two dimensional integer array is defined with 4 rows and 5 column matrix below. int matrix[4][5]=7, 3, 6, 9, 4, 10, 5, 1, 8, 7, 8, 6, 11, 13, 7, 5, 6, 8, 13, 16; (b) Write a program extract a portion of a character string and print the extracted string. Assume that m characters are extracted starting with nth character. #include<stdio.h> #include<string.h> #include<conio.h> main() char st[100]; int x,i,y,l; clrscr(); printf("enter the string\n"); gets(st); l=strlen(st); printf("how many char you want to extract "); scanf("%d",&x); printf("from where to? " ); scanf("%d",&y); printf("the extracted part of string is=\n"); for(i=0;i<y-1;i++) printf("%c\n",st[i]); for(i=(y+x-1); i<l; i++)

10 getch(); printf("%c\n",st[i]); (c) What are different types of string handling functions? Write a program to test whether the given input string is palindrome or not. Some different string handling functions are: strcat(str1,str2); This function concatenates two strings str1 and str2 and store the resulting string into str1. strcpy(str1,str2); This function copies the string of str2 into str1 strcmp(str1,str2); This function compares str1 and str2. If str1 and str2 matches then it returns 0. strlen(str1); This function computes and returns the length of the string str1. strstr(str1,str2); This function determines the occurrence of str2 in str1. Program: #include <string.h> int main() char a[100], b[100]; printf("enter the string to check if it is a palindrome\n"); gets(a); strcpy(b,a); strrev(b); if( strcmp(a,b) == 0 ) printf("entered string is a palindrome.\n"); else printf("entered string is not a palindrome.\n"); return 0; (d) Describe the limitations of using getchar() and scanf() for reading a string.

11 We know that string is declared in two ways. The most popular approach is using array of character as follows. char text[100]; another approach is to use pointer like char *text; In case of using the previous approach, we can store a string value in the variable text from keyboard using both getchar() and scanf() functions. But the technique will be different. Here we have written a program to get a string input from keyboard i.e. a series of characters will be entered and stored in the variable text until Enter key is pressed. for(count=0;text[count]=getchar()!= \n ;count++); A for loop is used to read a series of characters and store it into an array. But if we use scanf() function, we can easily write the code as follows. scanf( %s, text); Here %s control string is giving us a power to reduce the code and easy writing. 5(a) What is a function definition? Write down the general form of function definition. Function definition is the name of the function following the rules of identifier names along the formal parameters for passing values specified in the argument list and also the type that the value is returned by that function. The general form of a function is shown below: <Return type> function_name(<parameter type> parameter_name) (b) Distinguish between the following: (i) Actual and formal parameter (ii) Automatic and static variables

12 (i) Actual parameter and formal parameters are all parameter used for function, but the parameters in the line of function calling listed in the function calling statement within the braces are known as actual parameters and the variable names with its type definition within the function definition of a user defined function are known as formal parameters. Let us have an example void main() int num; display(num); Here num is the actual parameter when calling the display function. void display(int n) In the above example the variable n with the type of int is treated as formal parameter. (ii) Static variable We have to specify the storage class to make a variable static. If it is not assigned any value then it will give 0 as out put. It is visible to the block in which it is declared and also in the function where it will passed. It retains its value between different function calls. It holds its last value. Static variable should be compile by compiler first. Auto variable It is the default storage class. If it is not assigned any value then it will give garbage value as output. It is visible to the block in which the variable is declared. It retains its value till the control remains in the block in which the variable is declared. Auto variable will compile by the compiler after the static variable. (c) Create a structure which will store name, roll no, and marks of 6 courses that you obtained. This structure will also store total obtained marks. Store all the data for 10 students. Write a program in C to record students information according to their merit position.

13 #include <conio.h> typedef subject_marks float course1_marks; float course2_marks; float course3_marks; float course4_marks; float course5_marks; float course6_marks; float total_marks; ; typedef struct student char name[50]; int roll_no; subject_marks marks; ; void main() struct student student_records[10]; struct student temp_student_record; int count; // reading 10 students records with all course marks clrscr(); for(count=0;count<=9;count++) printf( \nstudent Roll No. %d :,count+1); student_record[count].roll_no=count+1; printf( Name: ); scanf( %s,student_record[count].name); printf( Course 1 Marks: ); scnaf( %f,&student_record[count].marks.course1_marks); printf( Course 2 Marks: ); scnaf( %f,&student_record[count].marks.course2_marks); printf( Course 3 Marks: ); scnaf( %f,&student_record[count].marks.course3_marks); printf( Course 4 Marks: ); scnaf( %f,&student_record[count].marks.course4_marks); printf( Course 5 Marks: ); scnaf( %f,&student_record[count].marks.course5_marks); printf( Course 6 Marks: ); scnaf( %f,&student_record[count].marks.course6_marks); // calculating total marks of each student

14 for(count=0;count<=9;count++) student_record[count].marks.total_marks=(student_record[count].marks.course1_marks+ student_record[count].marks.course2_marks+ student_record[count].marks.course3_marks+ student_record[count].marks.course4_marks+ student_record[count].marks.course5_marks+ student_record[count].marks.course6_marks); // sorting the records according to merit position or total marks in descending order int i, j; for(i=0;i<=8;i++) temp_student_record.roll_no=student_record[i].roll_no; temp_student_record.name=student_record[i].name; temp_student_record.marks.course1_marks=student_record[i].course1_marks; temp_student_record.marks.course2_marks=student_record[i].course2_marks; temp_student_record.marks.course3_marks=student_record[i].course3_marks; temp_student_record.marks.course4_marks=student_record[i].course4_marks; temp_student_record.marks.course5_marks=student_record[i].course5_marks; temp_student_record.marks.course6_marks=student_record[i].course6_marks; for(j=i;j<=9;j++) if (student_record[j].total_marks>temp_student_record.total_marks) student_record[i].roll_no=student_record[i].roll_no; student_record[i].name=student_record[i].name; student_record[i].marks.course1_marks=student_record[j].course1_marks; student_record[i].marks.course2_marks=student_record[j].course2_marks; student_record[i].marks.course3_marks=student_record[j].course3_marks; student_record[i].marks.course4_marks=student_record[j].course4_marks; student_record[i].marks.course5_marks=student_record[j].course5_marks; student_record[i].marks.course6_marks=student_record[j].course6_marks; student_record[j].roll_no=student_record[i].roll_no; student_record[j].name=student_record[i].name; student_record[j].marks.course1_marks=temp_student_record.course1_marks; student_record[j].marks.course2_marks=temp_student_record.course2_marks; student_record[j].marks.course3_marks=temp_student_record.course3_marks; student_record[j].marks.course4_marks=temp_student_record.course4_marks; student_record[j].marks.course5_marks=temp_student_record.course5_marks; student_record[j].marks.course6_marks=temp_student_record.course6_marks;

15 // displaying the sorted list clrscr(); printf( The sorted list according to merit position ); printf( \n Roll No. Name Total Marks Position ); for(i=0;i<=9;i++) printf( \n%d %s %f %dst, student_record[i].roll_no, student_record[i].name, student_record[i].total_marks,i); getche(); (d) What do you mean by Call by value and Call by reference? Let us have an example below. void main() swap(p,q); void swap(int x, int y) int temp; temp = x; /* save the value of x */ x = y; /* put y into x */ y = temp; /* put temp into y */ return; In above program segment, function swap is called from the main function with the values substituted in the parameters i.e. the value of variable p is substituted in variable x in swap function as well as value of q is in variable y respectively. This is known as Call by values. In the same way but instead of using call by values, we can use pointers or variables that hold the address of the values whose are to be operated. This is known as Call by reference and illustrated below. void swap(int *x, int *y) int temp; temp = *x; /* save the value at address x */ *x = *y; /* put y into x */ *y = temp; /* put temp into y */

16 return; 6(a) Describe the different types of file opening mode. The different file open modes also the corresponding file types are listed below: Opening modes File type Description Read only Mode r If a file exist, then the file is opened in read only mode Write only Mode w If a file exist, then it is destroyed and new file is created and opened for write only mode Both read and write Mode r+, w+ w+ will destroy the file if exist and new file will be created Append Mode only a If a file exists, it is opened for adding new information at the end of the file. If the file does not exist then a new file is created. Both read and append Mode (b) Describe about the error handling in file operation. a+ If a file exist then it is opened both for reading and appending, if doesn t exist then a new file is created C does not provide direct support for error handling also known as exception handling. By convention, the programmer is expected to prevent errors from occurring in the first place, and test return values from functions. For example, -1 and NULL are used in several functions. In a scenario where there is an unavoidable error and no way to recover from it, a C programmer usually tries to log the error and "gracefully" terminate the program. Let us have the following example. main() char *filename; FILE *fp1, *fp2; int i, number; fp1 = fopen("test", "w"); for(i = 10; i <= 100; i += 10) putw(i, fp1); fclose(fp1); printf("\ninput filename\n"); open_file: scanf("%s", filename); if((fp2 = fopen(filename,"r")) == NULL)

17 printf("cannot open the file.\n"); printf("type filename again.\n\n"); goto open_file; else for(i = 1; i <= 20; i++) number = getw(fp2); if(feof(fp2)) printf("\nran out of data.\n"); break; else printf("%d\n", number); fclose(fp2); In the above program we see that the file is opened with read only mode using the pointer fp and checked that whether the pointer value fp is null or not. If it is null then an error message is generated Cannot open the file and requested to retype the filename again. (c) Using the following declarations int x=10, y=10; int *p1=qx, *p2=qy; Determine the value of each of the following expression (i) (*p1)++ (ii) *p1+(*p2)-- (iii) --(*p2) (iv) ++(*p2)-*p1 Let us have the following assumptions. F8E qx F8E 10 x F8C qy F8C 10 y (i) (ii) F8F F19

18 (iii) F8B (iv) (d) A file named DATA contains some integer number. Write a file program which will produce all odd numbers in a file named ODD and all even numbers in a file named EVEN. #include <conio.h> #include <dos.h> void main() int i; FILE *fp; fp=fopen("sample.dat","w"); if(fp==null)printf("file cannot be opened!"); else clrscr(); printf("data are being written... \n"); for(i=1;i<=100;i++) fprintf(fp,"%d ",i); printf("%d ",i); delay(100); fclose(fp); printf("\ndata Saved."); getche(); In the above program SAMPLE.DAT file is created and 100 natural integers are written in the SAMPLE.DAT file. In the next program the abovementioned file is opened in read only mode and each and every integer is checked whether is odd or even and written into ODD.DAT and EVEN.DAT files respectively. #include <conio.h> void main() int num; FILE *fpt, *fpt1, *fpt2; fpt=fopen("sample.dat","r");

19 if(fpt==null) printf("file cannot be opened!"); getche(); else fpt1=fopen("odd.dat","w"); fpt2=fopen("even.dat","w"); printf("\ndata being extracted and saved in ODD and EVEN file..."); while((fscanf(fpt,"%d ",&num))!=eof) if((num%2)==0) fprintf(fpt2,"%d ",num); else fprintf(fpt1,"%d ",num); fclose(fpt1); fclose(fpt2); printf("\ndata saved."); getche(); fclose(fpt);

'C' Programming Language

F.Y. Diploma : Sem. II [DE/EJ/ET/EN/EX] 'C' Programming Language Time: 3 Hrs.] Prelim Question Paper Solution [Marks : 70 Q.1 Attempt any FIVE of the following : [10] Q.1(a) Define pointer. Write syntax