F.E. Sem. II. Structured Programming Approach

Transcription

1 F.E. Sem. II Structured Programming Approach Time : 3 Hrs.] Mumbai University Examination Paper Solution - May 14 [Marks : 80 Q.1(a) What do you mean by algorithm? Which points you should consider [4] while developing the algorithm. (A) Algorithm is a blueprint of a program. It can be considered as a stepwise procedure to solve a particular problem in finite number of steps. [4 marks] Following point s should be considered while developing an algorithm 1) Sequence : The sequence of the algorithm and as that of program should be same. 2) Correctness : The algorithm is said to be correct if its program correctly solve a problem. 3) Condition : There may be some conditional statements whose execution id depending on a particular condition. 4) Iteration : There may be some iterative statements whose execution will get repeated till there condition is true. 5) Termination : Each algorithm should get terminated correctly. Q.1(b) Determine the type of triangle, given its sides. (i.e. isosceles, [4] scalene, equilateral). Is the above problem definition is complete? if not, make this problem definition complete. (A) The problem definition is not complete. [4 marks] Problem definition : 1) Input : (a) No. of inputs - 03 (b) Type of inputs - integers 2) Output : (a) No. of output - 01 (b) Type of output - message 3) Process : Firstly, we need to accept 3 sides of a triangle and we need to check first whether the triangle can be drawn or not. If the triangle can be drawn then only we can classify it into isosceles, equilateral and scalene triangle. 1

2 : F.E. SPA 1. Start 2. Input sides are a, b, c respectively 3. if ((a + b > c && a + c > b && b + c > a) && (a > 0 && b > 0 && c > 0)) define s as perimeter value s = (a + b + c) / 2.0; define area area = sqrt((s * (s - a) * (s - b) * (s - c))); if (a == b && b == c) print message " It is Equilateral Triangle. " print Area of Equilateral Triangle. 4. else if (a == b b == c a == c) Print the message : Isosceles Triangle. Print Area of an Isosceles Triangle 5. else print the message : Scalene Triangle. Print "Area of Scalene Triangle Else print the message "Triangle formation not possible" 6. STOP Q.1(c) State any 2 library function in string.h along with its uses. [4] (A) [Library function 2 marks each] strcat() : This function concatenates one string at the end of other string. Example : char x[50] = hello ; char y[50] = all ; strcat(x,y) ; //this will make x = helloall Strcmp : This function compares one string with other string. The syntax is int z = strcmp(x,y); //here x and y are strings to be compared. 2

3 strcmp function will return Value > 0 if x >y (ie if first string is greater than second) Value < 0 if x <y (ie if first string is smaller than second) Value = 0 if x = y (ie if first string is equal to second) Example : char x[50] = abcd ; char y[50] = abc ; int z = strcmp(x,y); Here z > 0 as string x is larger than string y. strlen() : This function returns length of the string. Example : char x[50] = hello ; //x is array of 50 characters len = strlen(x); //here value of len = 5 as hello contains 5 characters May 14 Paper Solution Q.1(d) What do you mean by auto and extern storage class? Explain with [4] example. (A) A storage class defines the scope (visibility) and life time of variables and/or functions within a C Program. There are following storage classes which can be used in a C Program auto register static extern (a) auto - Storage Class auto is the default storage class for all local variables. int Count; auto int Month; [2 marks] The example above defines two variables with the same storage class. auto can only be used within functions, i.e. local variables. (b) extern - Storage Class [2 marks] extern is used to give a reference of a global variable that is visible to ALL the program files. When you use 'extern' the variable cannot be initalized as all it does is point the variable name at a storage location that has been previously defined. 3

4 : F.E. SPA When you have multiple files and you define a global variable or function which will be used in other files also, then extern will be used in another file to give reference of defined variable or function. Just for understanding extern is used to decalre a global variable or function in another files. File 1: main.c int count=5; main() write_extern(); File 2: write.c void write_extern(void); extern int count; void write_extern(void) printf("count is %i\n", count); Here extern keyword is being used to declare count in another file. Now compile these two files as follows gcc main.c write.c -o write This fill produce write program which can be executed to produce result. Count in 'main.c' will have a value of 5. If main.c changes the value of count - write.c will see the new value Q.1(e) Explain switch control statement with the help of example. [4] (A) A switch statement allows a variable to be tested for equality against a list of values. Each value is called a case, and the variable being switched on is checked for each switch case. [4 marks] Syntax: The syntax for a switch statement in C programming language is as follows: switch(expression) case constant-expression : statement(s); break; /* optional */ case constant-expression : statement(s); 4

5 break; /* optional */ /* you can have any number of case statements */ default : /* Optional */ statement(s); May 14 Paper Solution The following rules apply to a switch statement: The expression used in a switch statement must have an integral or enumerated type, or be of a class type in which the class has a single conversion function to an integral or enumerated type. You can have any number of case statements within a switch. Each case is followed by the value to be compared to and a colon. The constant-expression for a case must be the same data type as the variable in the switch, and it must be a constant or a literal. When the variable being switched on is equal to a case, the statements following that case will execute until a break statement is reached. When a break statement is reached, the switch terminates, and the flow of control jumps to the next line following the switch statement. Not every case needs to contain a break. If no break appears, the flow of control will fall throughto subsequent cases until a break is reached. A switch statement can have an optional default case, which must appear at the end of the switch. The default case can be used for performing a task when none of the cases is true. Nobreak is needed in the default case. 5

6 : F.E. SPA Example: #include<stdio.h> int main () /* local variable definition */ char grade ='B'; switch(grade) case'a': printf("excellent!\n"); break; case'b': case'c': printf("well done\n"); break; case'd': printf("you passed\n"); break; case'f': printf("better try again\n"); break; default: printf("invalid grade\n"); printf("your grade is %c\n", grade ); return0; When the above code is compiled and executed, it produces the following result: Well done Your grade is B Q.2(a) Write a program in C to delete all the occurrences of given number [10] from an ARRAY. For example, suppose ARRAY A = 2, 5, 3, 9, 2, 2, 3 and given no is 2 then after deletion ARRAY should have A = 5, 3, 9, 3 (A) #include<stdio.h> [10 marks] 6

7 int a[100],i,j,k,n; clrscr( ); printf("\nenter n"); scanf("%d",&n); for(i=0;i<n;i++) printf("\nenter number="); scanf("%d",&a[i]); for(i=0;i<n;i++) for(j=i+1;j<n;j++) if(a[i]==a[j]) for(k=j;k<n;k++) a[k]=a[k+1]; n--; printf("\nnew array is=\n"); for(i=0;i<n;i++) printf("\t%d",a[i]); getch(); May 14 Paper Solution Q.2(b) Write a program to check whether the given number is palindrome [10] or not. i.e if no is it is palindrome. (A) #include<stdio.h> [10 marks] int rev(int b) int rev=0,u; while(b>0) 7

8 : F.E. SPA u=b%10; rev=rev*10+u; b=b/10; return rev; int ispalin(int a) int palin; palin=rev(a); if(palin==a) return 1; else return 0; int n,res; clrscr( ); printf("enter the no\n"); scanf("%d",&n); res=ispalin(n); if(res==1) printf("number is palindrome\n"); else printf("number is not a palinidrome\n"); Q.3(a) What do you mean by Recursion? Write a program which will accept [10] two numbers, n and r and calculate value of nc r = n! / r! (n r)!. Program should make use of recursion. (A) A function that calls itself is known as recursive function and this technique is known as recursion in C programming. Program : #include<stdio.h> int fact(int b) [10 marks] 8

9 int i,fact=1; for(i=1;i<=b;i++) fact=fact*i; return fact; int n,r,x,y,z,ncr,npr; clrscr( ); printf("enter the n,r\n"); scanf("%d%d",&n,&r); x=fact(n); y=fact(r); z=fact(n-r); ncr=x/y*z; npr=x/z; printf("%d C %d is %d\n",n,r,ncr); printf("%d P %d is %d\n",n,r,npr); May 14 Paper Solution Q.3(b) Write a program to sort given nos in Ascending order. [10] (A) [10 marks] #include<stdio.h> int a[10],i,j,n,temp; clrscr( ); printf("enter the value of n\n"); scanf("%d",&n); printf("enter the element of an Array\n"); for(i=0;i<n;i++) scanf("%d",&a[i]); printf("before sorting\n"); for(i=0;i<n;i++) 9

10 : F.E. SPA printf("%d ",a[i]); for(i=1;i<n;i++) for(j=0;j<n;j++) if(a[j]>a[j+1]) temp=a[j]; a[j]=a[j+1]; a[j+1]=temp; printf("\nafter sorting\n"); for(i=0;i<n;i++) printf("%d ",a[i]); Q.4(a) A Hospital needs to maintain details of patients. Details to be [10] maintained are, First name, Middle name, Surname, Date of Birth, Disease. Write a C program which will print the list of all patients with given disease. (A) #include<stdio.h> [10 marks] struct patient char fname[20],mname[20],surname[20],dob[20],disease[20]; ; void main() struct patient p[100]; char d[20]; int i, n; printf( Enter number of patients ); scanf( %d, &n); for(i=0; i < n; i++) 10

11 May 14 Paper Solution printf( \nenter first name, middle name, last name, date of birth and disease ); scanf( %s%s%s%s%s, p[i].fname, p[i].mname, p[i].lname, p[i].surname, p[i].dob, p[i].disease); printf( \nenter disease to be searched ); scanf( %s, d); for(i = 0; i < n; i++) if(strcmp(p[i].disease,d) == 0) printf( \n%s%s%s, p[i].fname, p[i].mname, p[i].surname) Q.4(b) Write a program which will accept a 2 dimensional square matrix [10] and find out transpose of it. Program should not make use of another matrix. (A) #include<stdio.h> [10 marks] int a[10][10], n, i, j, t; clrscr( ); printf("\nenter n"); scanf("%d", &n); for(i = 0; i < n; i++) for(j = 0; j < n; j++) printf("\nenter elements="); scanf("%d", &a[i][j]); for(i = 0; i < n; i++) for(j = i + 1; j < n; j++) 11

12 : F.E. SPA t = a[i][j]; a[i][j] = a[j][i]; a[j][i] = t; for(i = 0; i < n; i++) for(j = 0; j < n; j++) printf("%d", a[i][j]); printf("\n"); Q.5(a) Write a program to generate following patterns. (i) 1 (ii) * 2 3 * * * * * * * * (A) (i) Program #include<stdio.h> int i, j, n, a; clrscr( ); printf("enter the no. of rows"); scanf("%d", &n); a = 1; for(i = 1; i <= n; i++) for(j = 1; j <= i; j++) printf("%d", a); a++; printf("\n"); [10] [5 marks] 12

13 May 14 Paper Solution (ii) Program #include<stdio.h> int i, j; for(i = 1; i < 3; i++) for(j = 1; j <= 3 - I; j++) printf( ); for(j = 1; j <= i; j++) printf( * ); printf( \n ); for(i = 2; i >= 1; i--) for(j = 1; j <= 3 - I; j++) printf( ); for(j = 1; j <= i; j++) printf( * ); printf( \n ); [5 marks] Q.5(b) Write a C program to multiply 2 matrices after checking compatibility. Your program should make use of function to accept element of matrix, display matrix, and multiply matrix. [10] 13

14 : F.E. SPA (A) #include<stdio.h> [10 marks] int m, n, p, i, j, a[10][10], b[10][10]; void mul(int a[10][10], int b[10][10], int m, int n, int p); printf( Enter number of rows and columns of matrix 1 ); scanf( %d%d, &m, &n); printf( Enter the values of matrix1 ); for(i = 0, i < m; i++) for(j = 0; j < n; j++) printf( \nenter value= ); scanf( %d,&a[i][j]); printf( \nthe number of rows of matrix 2 is=%d, n); printf( \nenter number of columns of matrix 2 ); scanf( %d,&p); printf( Enter the values of matrix2 ); for(i = 0, i < n; i++) for(j = 0; j < p; j++) printf( \nenter value= ); scanf( %d, &b[i][j]); mul(a, b, m, n, p); void mul(int a[10][10], int b[10][10], int m, int n, int p) int i, j, k, c[10][10]; for(i = 0; i < m; i++) for(j = 0; j < p; j++) c[i][j] = 0; 14

15 for(k = 0; k < n; k++) c[i][j]+ = a[i][k]*b[k][j]; printf( \nthe resultant matrix \n ); for(i = 0; i < m; i++) for(j = 0; j < p; j++) printf( %d, c[i][j]); printf( \n ); May 14 Paper Solution Q.6(a) Write a program to calculate summation of series. [10] 1/2 3/4 + 5/6 7/8 +. upto n terms. (A) #include<stdio.h> [10 marks] int n, i, z = 1, a = 1, b = 2; float s=0.0; printf( \nenter n ); scanf( %d, &n); for(i = 1; i <= n; i++) s = s + (a/b)*z; a = a + 2; b = b + 2; z = -z; printf( \nsummation=%f,s); Q.6(b) What do you mean by FILE? What are the different functions available to read data from file? Specify the different modes in which file can be opened along with syntax. [10] 15

16 : F.E. SPA (A) Abstractly, a file is a collection of bytes stored on a secondary storage device, which is generally a disk of some kind. The collection of bytes may be interpreted, for example, as characters, words, lines, paragraphs and pages from a textual document; fields and records belonging to a database; or pixels from a graphical image. The meaning attached to a particular file is determined entirely by the data structures and operations used by a program to process the file. [10 marks] Different functions to read file : fgetc( ) The fgetc( ) function reads a character from the input file referenced by fp. The return value is the character read, or in case of any error it returns EOF. fgets( ) The functions fgets( ) reads up to n - 1 characters from the input stream referenced by fp. It copies the read string into the buffer buf, appending a null character to terminate the string. If this function encounters a newline character '\n' or the end of the file EOF before they have read the maximum number of characters, then it returns only the characters read up to that point including new line character. fscanf( ) You can also use fscanf function to read strings from a file but it stops reading after the first space character encounters. Different modes in which file can be read : Mode Description r Opens an existing text file for reading purpose. w Opens a text file for writing, if it does not exist then a new file is created. Here your program will start writing content from the beginning of the file. a Opens a text file for writing in appending mode, if it does not exist then a new file is created. Here your program will start appending content in the existing file content. r+ Opens a text file for reading and writing. w+ Opens a text file for reading and writing both. It first truncate the file to zero length if it exists otherwise create the file if it does not exist. a+ Opens a text file for reading and writing both. It creates the file if it does not exist. The reading will start from the beginning but writing can only be appended. 16