Counting Positive Negative Numbers From A File lex Program

Compiler Construction Lab Manual / Counting Positive Negative Numbers From A File lex Program

Program Name

Write a Compiler Construction Program for Counting Positive Negative Numbers From A File lex Program.

Theory
Counting Positive Negative Numbers From A File lex Program

Program Code


%{
#include<stdio.h>
int positive;
int negative;
%}
digit [0-9]
number {digit}*
%%
[+]?{number} {positive++;}
[-]?{number} {negative++;}
%%
int main(int argc,char *argv[])
{
yyin=fopen(argv[1],"r");
yylex();
printf("no of positive numbers=%d\n no of negative numbers=%d\n",positive,negative);
fclose(yyin);
return 0;
}
int yywrap(void){	return 1;	}

Saving: vi positive.l

Compiling and Running
lex positive.l
cc lex.yy.c
./a.out file2.c

Input
//Vi file2.c +1
2
6
-9
6
8
-4
-5
-6
+2
+4

Output
no of positive numbers=7 no of negative numbers=4

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