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1 Test Paper 3 Programming Language Solution Question 1: Briefly describe the structure of a C program. A C program consists of (i) functions and (ii) statements There should be at least one function called main function and other user defined functions may exist in a program. A function has (i) function definition e.g. main() is name of the main function and a function can either return a value or not. If a function does not return a value is defined as void main(). But any other function may return value of some type like integer, char etc. int add(int a, int b); int sum; sum=add(3,4); printf( %d, sum); int add(int a, int b) return(a+b); In the above program, main function is defined as because it doesn t return any value but an user defined function add() is also defined and written which returns a value of integer type. Every function header is immediately followed by opening and closing parenthesis. There can either be no arguments or one or more arguments. In the above program, main function has no arguments but function add has two arguments in which both the parameters are defined by the data type (int a, int b). Statements are written in each and every function. In the above program, statements are written in both the functions main() and add() like sum=add(3,4), printf( %d,sum); and return(a+b);. Any compound statements can also be written within any function. Question 2: Draw the flowchart that shows the process of compiling and running a C program.

2 start Encode and Edit the program Compile Yes Error No Link Run Question 3: Briefly explain different form of main function of a C program A program written in C language must consist of a main function. A main function can either be a function with no returning value with no argumentation or it can return any type of data value with parameter passing In the above program segment, a main function is defined as void that returns no value and no parameter specified within the parenthesis (). Another form of main function is shown below. End

3 addition.cpp int main(int argc[],argv[]) int sum; if(argc[]==0)printf( No input value specified ); else if(argc[]=2)sum=argv[0]+argv[1]; return(sum); The above program receives input values through command line arguments and add them together and return the integer type result of summation of the input values. Question 4: Write a program to find the area of a circle. #define PI float radius, area; printf( Enter Radidus: ); scanf( %f,radius); area=pi*radius*radius; printf( Area of the circle: %7.3f,area); Question 5: What are trigraph characters? How are they useful? Trigraph characters are sequence of three characters that represent one character from ASCII character set. This is ANSI standard practice in C language. This feature may not be available in Turbo C compiler. Usage of trigraph sequence is shown in the following example. Printf( Hellow world??!#n ); While executing the above statement, the output will appear as follows: Hellow world Here two successive question sign followed by exclamatory sign which completes a trigraph sequence will produce a which is a character of ASCII character set on the output screen immediately after the text. A list of trigraph sequence is shown below.??= #??( [??/ \??) ]??' ^??<??!??>??- ~

4 Question 6: How do variables and symbolic names differ? Show with example. A variable is declared with the data type and its name, e.g. int x; here x is a variable name that holds integer type of data. x is variable written in a main function that comes into existence while executing. But symbolic names also known as symbolic constant are defined above the main function just immediately after the header files included conventionally, e.g. #define PI 3.14 Here PI is a symbolic constant with value 3.14 that cannot be changed throughout the program. Question 7: What are the rules for declaring identifiers? Variables, functions and arrays are treated as identifiers. Identifiers are consist of letters and digits as well as the first character must be a letter, both upper case and lower case letters are permitted though lower case letters are usually considered for practice. In this case, upper case letter and lower case letter is not equivalent. An underscore (_) character can also be included in an identifier. Question 8: What is storage class? What are the meaning of storage class? Storage class refers to the permanence of a variable and its scope within a progam that the portion of the program over which the variable is recognized. The four different storage class specifications are automatic, external, static and register identified by the keyword auto, extern, static and register respectively. Automatic variables are always declared within a function and are local to the functions in which they are declared. External variables scopes are extended from the point of their definition to the rest of the program. Static variables are defined within individual functions and have same scope as automatic variables. Question 9: Write a program to convert the given temperature in Fahrenhite to Celcius and vice versa. Formula: (i) C(9/5)+32=F (ii) (F-32)(5/9)=C

5 void ftoc(); //function prototype void ctof(); //function prototype int choice; clrscr(); printf( [1]. Farhenhite to Celcius [2]. Celcius to Farhenhitle\n ); printf( Type 1 or 2 for conversion mode: ); scanf( %d,&choice); if (choice==1)ftoc(); else if (choice==2)ctof(); else printf( Error in choice... ); void ftoc() float f,c; printf( \n ); printf( Enter Farhenhite temperature: ); scanf( %f,&f); c=(f-32.0)*(5.0/9.0); printf( The temperature in celcius: %f,c); return; void ctof() float f,c; printf( \n ); printf( Enter celcius temperature: ); scanf( %f,&c); f=c*(9.0/5.0)+32.0; printf( The temperature in farhentile: %f,f); return; Question 10: Describe nesting of IF-ELSE statement with flow chart an example. A general form of nested if-else: If <condition 1> if <condition 2> <expression 1> else if <condition 3> <expression 2> else <expression 3>. The flowchart of above nested if structure is shown below.

6 No cond1 Yes No Cond2 Yes exp 3 exp 2 exp 1 Question 11: Write down the De-Morgan s rule in the case of decision making and branching. De-Morgan s rule tells us to convert a logical expression into such a form that consists of a NOT operator. For example if the value of i is less than 8 then iterate. According De-Morgan s rule, this expression will become if the value of i not greater than 8 then iterate. Using C syntax, it can be written as while (!(i>8))... Question 12: Write a program that read the value of x and evaluate the following function using if statement and?: operator. 1 for x > 0 y = 0 for x = 0 1 for x < 0 (i) using if statement: float x; int y; printf( Enter value of x: ); scanf( %d,&f); if (x>1.0)y=1; else if (x==0.0)y=0; else if (x<0.0)y=-1; printf( y = %d,y);

7 (ii) using?: operator float x; int y; printf( Enter value of x: ); scanf( %d,&f); y=(x>1.0)? 1 : ((x==0.0)? 0 : -1); printf( y = %d,y); Question 13: What is array? Why an array is called structured data types? 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]; Question 14: Write a program to set all diagonal elements of a two dimensional array to 1 and others to 0. int x[20][20]; int i,j,n; clrscr(); printf("enter size of a square matrix [less than 20]: "); scanf("%d",&n); // putting 0s to all matrix elements for(j=0;j<n;j++) x[i][j]=0;

8 // substituing 1s on the left diagonal for(j=0;j<n;j++) if(i==j)x[i][j]=1; // substituting 1s on the right diagonal j=0; for(i=n-1;i>=0;i--) x[i][j]=1; j++; // printing the matrix for(j=0;j<n;j++) printf("%d ",x[i][j]); Question 15: Character string in C terminates with null character. Explain how this feature helps in string manipulation. In C language Strings are defined as an array of characters or a pointer to a portion of memory containing ASCII characters. A string in C is a sequence of zero or more characters followed by a NULL '\0' character. It is important to preserve the NULL terminating character as it is how C defines and manages variable length strings. If we were to have an array of characters WITHOUT the null character as the last element, we'd have an ordinary character array, rather than a string constant. String constants have double quote marks around them, and can be assigned to char pointers. Alternatively, we can assign a string constant to a char array - either with no size specified, or we can specify a size, but we should leave a space for the null character! Question 16: Briefly explain atoi() with suitable example. atoi function converts a string into an int value. It includes whitespace, punctuation and characters other that E and e. It returns only the integer part of the value returned and decimal part is truncated. Example #include <stdlib.h>

9 char str1[100],str2[100]; printf( Type first string: ); gets(str1); printf( Type another string: ); gets(str2); printf( Ths sum is %d, atoi(str1)+atoi(str2)); return 0; Question 17: Find errors, if any, in the following code segments (a) char str[10]; strncpy(str, GOD,3); printf( %s, str); (b) char str[10]; strcpy(str, Balagursami ); (c) if(strstr( Balagurusami, guru )==0);printf( Substring is found ); (d) char s1[5],s2[10]; gets(s1,s2); (e) char s1[]= Hello, s2[]- World,s3[8]; strcpy(strcat(s1,s2),s3); (a) char str[10]; strcpy(str, GOD ); printf( %s,str); (b) char str[20]; strcpy(str, Balagurusami ); (c) if(strcat( Balagurusami, guru )==0)printf( Substring is found ); (d) char s1[5],s2[10]; gets(s1); gets(s2) (e) char s1[]= Hello, s2[]= World, s3[10]; strcpy(s3,strcat(s1,s2)); Question 18: Describe different types of string-handling functions with meaning and example. 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.

10 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. Question 19: Write a program to find the number and sum of all integers greater than 100 and less than 200 that are divisible by 7 using function. 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=100;i<=200;i++) temp=generate_number(i); if(temp!=0) values[index]=temp; index++; sum=summation(values,index); printf("sum = %d",sum); int generate_number(int x) if((x%7)==0) printf("%d, ",x); return(x); else return 0; int summation(int x[],int n) int s,i; s=0;

11 s=s+x[i]; return(s); Question 20: Write a program in C to add and subtract two same size matrix. int matrix1[100][100],matrix2[100][100]; int matrix_added[100][100],matrix_subtracted[100][100]; int m,n,i,j; // input values to matrices clrscr(); printf("enter size of the matrices [m*n]"); printf("\n m=? "); scanf("%d",&m); printf("\n n=? "); scanf("%d",&n); printf("\nmatrix 1:\n"); printf("cell [i][j]:"); scanf("%d",&matrix1[i][j]); printf("\nmatrix 2:\n"); printf("cell [i][j]:"); scanf("%d",&matrix2[i][j]); // displaying the input matrices clrscr(); printf("the input matrices are..."); printf("\nmatrix 1:\n"); printf("%d ",matrix1[i][j]);

12 printf("\npress Enter... "); printf("\nmatrix 2:\n"); printf("%d ",matrix2[i][j]); printf("\npress Enter... "); //adding two matrics matrix_added[i][j]=matrix1[i][j]+matrix2[i][j]; //dispalying the matrix addition clrscr(); printf("\ntwo matrices added:\n"); printf("%d ",matrix_added[i][j]); printf("\npress Enter..."); //subtracting two matrics matrix_subtracted[i][j]=matrix1[i][j]-matrix2[i][j]; //dispalying the matrix subtraction printf("\ntwo matrices subtracted:\n"); printf("%d ",matrix_subtracted[i][j]);

13 printf("\npress Enter..."); Question 21: What is pointer? Write down the benefits of pointer uses in C program. Pointer is variable whose value is the address or memory location of another variable. For example, pu=&u; pu is a variable which holds the address of the variable u. Here pu is a pointer to u and pu is defined as follows. int *pu; Benefits of using pointers: pointers are generally useful in the context where we need a continuous memory allocation. Using pointers dynamic allocation of memory is achieved pointers basically hold the address of a variable. they are mainly used as function parameters to pass values of parameters as references rather than values Question 22: How can you define a FILE in C? Describe the opening and closing function of a FILE. A file is defined in C in following manner. FILE *fp; Here FILE is a keyword and a file pointer fp is associated with it. A file can be opened with various mode of operation. If a file named Sample.dat is opened with read mode then we can write in C language as follows. fopen( Sample.dat, r ); When the file is to be closed after read operation which was associated with file pointer fp, then the file should be closed in following manner. fclose(fp); Question 23: A file named DATA contains a series of integer numbers. Code a program to read these numbers and then write all odd numbers to a file to be called ODD and all even numbers to a file to be called EVEN.

14 #include <dos.h> 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."); 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. int num; FILE *fpt, *fpt1, *fpt2; fpt=fopen("sample.dat","r"); if(fpt==null) printf("file cannot be opened!"); 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)

15 fprintf(fpt2,"%d ",num); else fprintf(fpt1,"%d ",num); fclose(fpt1); fclose(fpt2); printf("\ndata saved."); fclose(fpt);

Unit 1 - Arrays. 1 What is an array? Explain with Example. What are the advantages of using an array?

Unit 1 - Arrays. 1 What is an array? Explain with Example. What are the advantages of using an array? 1 What is an array? Explain with Example. What are the advantages of using an array? An array is a fixed-size sequenced collection of elements of the same data type. An array is derived data type. The