Question

Write a program to reverse a word in a given string that is present in an input file.
Enter input file = file.txt
Enter line = "Hello how are you?"
Which word to reverse = 2
Hello woh are you?
Note: Input file (file.txt) can contain few lines including "Hello how are you?" After reversing the word​

Answer 1

Answer:

CODE:-

/*Lex program to take input from file and

remove multiple spaces, newline and tab

and write output in a separate file*/

% {

/*Definition section */

%

}

/* Rule: whenever space, tab or

newline is encounterd, remove it*/

% %

[ \n\t]+ {fprintf(yyout, "");}

. { fprintf(yyout, "%s", yytext); }

% %

int yywrap(){}

// driver code

int main()

{

/* yyin and yyout as pointer

of File type */

extern FILE *yyin, *yyout;

/* yyin points to the file input.txt

and opens it in read mode*/

yyin = fopen("Input.txt", "r");

/* yyout points to the file output.txt

and opens it in write mode*/

yyout = fopen("Output.txt", "w");

yylex();

return 0;

}