pattern_matching2.c

#include<stdio.h>
#include<string.h>
#include<stdlib.h>

void read();
void display();
void pattern();

char mainstr[100],patstr[100],repstr[100],tempstr[100];

void main()
{
	system("clear");
	read();
	system("clear");
	display();
	pattern();
}

void read()
{
	printf("Enter the main string ,pattern string and replacement string :\n");
	gets(mainstr);
	gets(patstr);
	gets(repstr);
}

void display()
{
	printf("The entered main string ,pattern string and replacement string are:\n");
	puts(mainstr);
	puts(patstr);
	puts(repstr);
}

void pattern()
{
	int mi=0,pi=0,ti=0,ci=0,ri=0,flag=0;
	while(mainstr[mi]!='\0')
	{
		if(mainstr[ci]==patstr[pi])
		{
			ci++;
			pi++;
			if(patstr[pi]=='\0')
			{
				for(ri=0;repstr[ri]!='\0';ri++)
				{
					tempstr[ti]=repstr[ri];
					ti++;
				}
				mi=ci;
				pi=0;
				flag=1;
			}
		}
		else
		{
			tempstr[ti]=mainstr[mi];
			ti++;
			mi++;
			ci=mi;
			pi=0;
		}
	}
	if(flag==0)
	{
		printf("Pattern does not found.\n");
	}
	else
	{
		tempstr[ti]='\0';
		printf("The final string is :");
		puts(tempstr);
	}
}