WAP to check a string is Caliondrome or not. // Maventic question.

Questions: Top-30-c-programs-asked-in-interview_6304.html

21. .WAP to check a string is Caliondrome or not. // Maventic question.

#include

#include

void main()

{

int i,j=0; char a[100];

clrscr();

printf("\n Enter the string to check for caliondrom e:\n");

gets(a);

if(strlen( a)%6)

{

printf("\n %s: is Not a caliondrom e..",a);

getch();

exit(0);

}

for (i=0;a[i]! ='\0'

{

if((a[i]== a[i+5])&&( a[i+1]==a[ i+4])&&(a[ i+2]==a[i+ 3]))

i=i+6;

else

{

j=1;

break;

}

}

if(j)

printf("\n %s: is Not a caliondrom e..",a);

else

printf("\n %s: is a caliondrom e..",a);

getch();

}

Write a program to display the multiplica tion table of a given number.

Questions: Top-30-c-programs-asked-in-interview_6304.html

20.Write a program to display the multiplica tion table of a given number.
Program: Multiplica tion table of a given number
#include
int main(){
int num, i = 1;
printf("\n Enter any Number:");
scanf("%d" ,&num);
printf("Mu ltiplicati on table of %d: \n", num);
while (i
printf("\n %d x %d = %d", num, i, num * i);
i++;
}
return 0;
}
Output:
Enter any Number:5
5 x 1 = 5
5 x 2 = 10
5 x 3 = 15
5 x 4 = 20
5 x 5 = 25
5 x 6 = 30
5 x 7 = 35
5 x 8 = 40
5 x 9 = 45
5 x 10 = 50
Explanatio n:
We need to multiply the given number (i.e. the number for which we want the multiplica tion table)
with value of'i'which increments from 1 to 10.

Write a C program which asks the user for a number between 1 to 9 and shows the number. If the user inputs a number out of the specified range, the program should show an error and prompt the user for a valid input.

Questions: Top-30-c-programs-asked-in-interview_6304.html

19.Write a C program which asks the user for a number between 1 to 9 and shows the number. If the user inputs a number out of the specified range, the program should show an error and prompt
the user for a valid input.
Program: Program for accepting a number in a given range.
#include
int getnumber( );
int main(){
int input = 0;
//call a function to input number from key board
input = getnumber( );
//when input is not in the range of 1 to 9,print error message
while (!((input = 1))){
printf("[E RROR] The number you entered is out of range");
//input another number
input = getnumber( );
}
//this function is repeated until a valid input is given by user.
printf("\n The number you entered is %d", input);
return 0;
}/
/this function returns the number given by user
int getnumber( ){
int number;
//asks user for a input in given range
printf("\n Enter a number between 1 to 9 \n");
scanf("%d" ,&number);
return (number);
}
Output:
Enter a number between 1 to 9
45
[ERROR] The number you entered is out of range
Enter a number between 1 to 9
4
The number you entered is 4
Explanatio n:
getfunctio n() function accepts input from user.'while'loop checks whether the number falls within range or not
and accordingl y either prints the number(If the number falls in desired range) or shows error message(nu mber is
out of range).

Write a program to find the number of lines in a text file.

Questions: Top-30-c-programs-asked-in-interview_6304.html

18.Write a program to find the number of lines in a text file.
Number of lines in a file can be determined by counting the number of new line characters present.
Program: Program to count number of lines in a file.
#include
int main()
/* Ask for a filename and count number of lines in the file*/
{
//a pointer to a FILE structure
FILE *fp;
int no_lines = 0;
// consider 40 character string to store filename
char filename[4 0], sample_chr ;
//asks user for file name
printf("En ter file name:");
// receives file name from user and stores in a string named'filename'
scanf("%s" , filename);
//open file in read mode
fp = fopen(file name,"r");
//get character from file and store in sample_chr
sample_chr = getc(fp);
while (sample_ch r != EOF){
// Count whenever sample_chr is'\n'(new line) is encountere d
if (sample_ch r =='\n')
{
// increment variable'no_lines' by 1
no_lines=n o_lines+1;
}
//take next character from file.
sample_chr = getc(fp);
}
fclose(fp) ; //close file.
printf("Th ere are %d lines in %s \n", no_lines, filename);
return 0;
}
Output:
Enter file name:abc.t xt
There are 4 lines in abc.txt
Explanatio n:
In this program, name of the file to be read is taken as input. A file by the given name is opened in read-mode
using a File pointer'fp'. Characters from the file are read into a char variable'sample_ch r'with the help of getc
function. If a new line character( '\n') is encountere d, the integer variable'no_lines' is incremente d. If the
character read into'sample_ch ar'is not a new line character, next character is read from the file. This process is
continued until the last character of the file(EOF) is encountere d. The file pointer is then closed and the total
number of lines is shown as output.

Write a program to replace a specified line in a text file.

Questions: Top-30-c-programs-asked-in-interview_6304.html

17.Write a program to replace a specified line in a text file.
Program: Program to replace a specified line in a text file.
#include
int main(void) {
FILE *fp1, *fp2;
// 'filename'i s a 40 character string to store filename
char filename[4 0];
char c;
int del_line, temp = 1;
//asks user for file name
printf("En ter file name:");
// receives file name from user and stores in'filename'
scanf("%s" , filename);
fp1 = fopen(file name,"r");
//open file in read mode
c = getc(fp1);
//print the contents of file .
while (c != EOF){
printf("%c ", c);
c = getc(fp1);
}
//ask user for line number to be deleted.
printf("\n Enter line number to be deleted and replaced") ;
scanf("%d" ,&del_line) ;
//take fp1 to start point.
rewind(fp1 );
//open copy.c in write mode
fp2 = fopen("cop y.c","w");
c = getc(fp1);
while (c != EOF){
if (c =='\n'){
temp++;
}
// till the line to be deleted comes,copy the content from one file to other
if (temp != del_line){
putc(c, fp2);
}
else //when the line to be deleted comes
{
while ((c = getc(fp1)) !='\n'){
}
//read and skip the line ask for new text
printf("En ter new text");
//flush the input stream
fflush(std in);
putc('\n', fp2);
//put'\n'in new file
while ((c = getchar()) !='\n')
putc(c, fp2);
//take the data from user and place it in new file
fputs("\n" , fp2);
temp++;
}
// continue this till EOF is encountere d
c = getc(fp1);
}
//close both files
fclose(fp1 );
fclose(fp2 );
//remove original file
remove(fil ename);
//rename new file with old name opens the file in read mode
rename("co py.c", filename);
fp1 = fopen(file name,"r");
//reads the character from file
c = getc(fp1);
// until last character of file is encountered
while (c != EOF){
printf("%c ", c);
// all characters are printed
c = getc(fp1);
}
//close the file pointer
fclose(fp1 );
return 0;
}
Output:
Enter file name:abc.t xt
hi.
hello
how are you?
hope the same
Enter line number of the line to be deleted and replaced:4
Enter new text: sayonara see you soon
hi.
hello
how are you?
sayonara see you soon
Explanatio n:
In this program, the user is asked to type the name of the file. The File by name entered by user is opened in
read mode. The line number of the line to be replaced is asked as input. Next the data to be replaced is asked. A
new file is opened in write mode named"copy.c". Now the contents of original file are transferre d into new file
and the line to be modified is deleted. New data is stored in its place and remaining lines of the original file are
also transferre d. The copied file with modified contents is replaced with the original file's name. Both the file
pointers are closed and the original file is again opened in read mode and the contents of the original file is
printed as output.

Write a program to delete a specified line from a text file.

Questions: Top-30-c-programs-asked-in-interview_6304.html

16. Write a program to delete a specified line from a text file.
In this program, user is asked for a filename he needs to change. User is also asked for the line number that is
to be deleted. The filename is stored in'filename' . The file is opened and all the data is transferre d to another file
except that one line the user specifies to delete.
Program: Program to delete a specific line.
#include
int main(){
FILE *fp1, *fp2;
// consider 40 character string to store filename
char filename[4 0];
char c;
int del_line, temp = 1;
//asks user for file name
printf("En ter file name:");
// receives file name from user and stores in'filename'
scanf("%s" , filename);
//open file in read mode
fp1 = fopen(file name,"r");
c = getc(fp1);
//until the last character of file is obtained
while (c != EOF)
{
printf("%c ", c);
//print current character and read next character
c = getc(fp1);
}
//rewind
rewind(fp1 );
printf("\n Enter line number of the line to be deleted:") ;
//accept number from user.
scanf("%d" ,&del_line) ;
//open new file in write mode
fp2 = fopen("cop y.c","w");
c = getc(fp1);
while (c != EOF){
c = getc(fp1);
if (c =='\n')
temp++;
//except the line to be deleted
if (temp != del_line)
{
//copy all lines in file copy.c
putc(c, fp2);
}
}
//close both the files.
fclose(fp1 );
fclose(fp2 );
//remove original file
remove(fil ename);
//rename the file copy.c to original name
rename("co py.c", filename);
printf("\n The contents of file after being modified are as follows:\n ");
fp1 = fopen(file name,"r");
c = getc(fp1);
while (c != EOF){
printf("%c ", c);
c = getc(fp1);
}
fclose(fp1 );
return 0;
}
Output:
Enter file name:abc.t xt
hi.
Hello
how are you?
I am fine
hope the same
Enter line number of the line to be deleted:4
The contents of file after being modified are as follows:
hi.
hello
how are you?
hope the same
Explanatio n:
In this program, user is asked for a filename that needs to be modified. Entered file name is stored in a char
array'filename' . This file is opened in read mode using file pointer'fp1'. Character'c'is used to read characters
from the file and print them to the output. User is asked for the line number in the file to be deleted. The file
pointer is rewinded back and all the lines of the file except for the line to be deleted are copied into another file
"copy.c". Now"copy.c"is renamed to the original filename. The original file is opened in read mode and the
modified contents of the file are displayed on the screen.

Write a program to concatenat e two strings without using strcat() function.

Questions: Top-30-c-programs-asked-in-interview_6304.html

15.Write a program to concatenat e two strings without using strcat() function.

strcat(str ing1,strin g2) is a C standard function declared in the header file string.h

The strcat() function concatenat es string2, string1 and returns string1.

Program: Program to concatenat e two strings

#include

#include

char *strct(cha r *c1, char *c2);

char *strct(cha r *c1, char *c2){

//strlen function returns length of argument string

int i = strlen(c1) ;

int k = 0;

// loops until null is encountered and appends string c2 to c1

while (c2[k] !='\0'){

c1[i + k] = c2[k];

k++;

}

return c1;

}

int main(){

char string1[15 ] ="first";

char string2[15 ] ="second";

char *finalstr;

printf("Be fore concatenat ion:"

"\n string1 = %s \n string2 = %s", string1, string2);

// addresses of string1, string2 are passed to strct()

finalstr = strcat(str ing1, string2);

printf("\n After concatenat ion:");

//prints the contents of string whose address is in finalstr

printf("\n finalstr = %s", finalstr);

//prints the contents of string1

printf("\n string1 = %s", string1);

//prints the contents of string2

printf("\n string2 = %s", string2);

return 0;

}

Output:

Before concatenat ion:

string1 = first

string2 = second

After concatenat ion:

finalstr = firstsecon d

string1 = firstsecon d

string2 = second

Explanatio n:

string2 is appended at the end of string1 and contents of string2 are unchanged.

In strct() function, using a for loop, all the characters of string'c2'are copied at the end of c1. return (c1) is

equivalent to return&c1[0] and it returns the base address of'c1'.'finalstr' stores that address returned by the

function strct().

Write a program to compare two strings without using strcmp() function.

Questions: Top-30-c-programs-asked-in-interview_6304.html

14.Write a program to compare two strings without using strcmp() function.
strcmp() function compares two strings lexicograp hically. strcmp is declared in stdio.h
Case 1: when the strings are equal, it returns zero.
Case 2: when the strings are unequal, it returns the difference between ascii values of the characters that differ.
a) When string1 is greater than string2, it returns positive value.
b) When string1 is lesser than string2, it returns negative value.
Syntax:
int strcmp (const char *s1, const char *s2);
Program: to compare two strings.
#include
#include
int cmpstr(cha r s1[10], char s2[10]);
int main(){
char arr1[10] ="Nodalo";
char arr2[10] ="nodalo";
printf("%d", cmpstr(arr 1, arr2));
// cmpstr() is equivalent of strcmp()
return 0;
}/
/s1, s2 are strings to be compared
int cmpstr(cha r s1[10], char s2[10]){
//strlen function returns the length of argument string passed
int i = strlen(s1) ;
int k = strlen(s2) ;
int bigger;
if (i<k){
bigger = k;
}
else if (i>k){
bigger = i;
}
else{
bigger = i;
}
//loops'bigger'times
for (i = 0; i<bigger; i++){
// if ascii values of characters s1[i], s2[i] are equal do nothing
if (s1[i] == s2[i]){
}
//else return the ascii difference
else{
return (s1[i] - s2[i]);
}
}
//return 0 when both strings are same
//This statement is executed only when both strings are equal
return (0);
}
Output:
-32
Explanatio n:
cmpstr() is a function that illustrate s C standard function strcmp(). Strings to be compared are sent as arguments
to cmpstr().
Each character in string1 is compared to its correspond ing character in string2. Once the loop encounters a
differing character in the strings, it would return the ascii difference of the differing characters and exit.

Write a program to print a semicolon without using a semicolon anywhere in the code.

Questions: Top-30-c-programs-asked-in-interview_6304.html

13.Write a program to print a semicolon without using a semicolon anywhere in the code.
Generally when use printf("") statement we have to use semicolon at the end.
If we want to print a semicolon, we use the statement: printf(";" );
In above statement, we are using two semicolons . The task of printing a semicolon without using semicolon anywhere in the code can be accomplish ed by using the ascii value of';'which is equal to 59.
Program: Program to print a semicolon without using semicolon in the code.
#include
int main(void) {
//prints the character with ascii value 59, i.e., semicolon
if (printf("% c\n", 59)){
//prints semicolon
}
return 0;
}
Output:
;
Explanatio n:
If statement checks whether return value of printf function is greater than zero or not. The return value of function
call printf("%c ",59) is 1. As printf returns the length of the string printed. printf("%c ",59) prints ascii value that
correspond s to 59, that is semicolon( .