NAIVE STRING MATCHING Algorithm

Algorithm: NAÏVE_STRING_MATCHER (T, P)

n ← length [T]
m ← length [P]
for s ← 0 to n - m do
    if P[1 . . m] = T[s +1 . . s + m]
        then return valid shift s

C program:

#include<stdio.h>

#include<stdlib.h>

#include<string.h>

main()

{

char p[50],t[50];

int i,j,n,m,flag=-1;

printf("enter the main string \n");

scanf("%s",t);

printf("enter the pattern \n");

scanf("%s",p);

n=strlen(t);

m=strlen(p);

for(i=0;i<=n-m;i++)

{

j=0;

while(j<m && p[j]==t[i+j])

{

j++;

}

if(j==m)

{

flag=0;

printf("string is found at %d\n",i);

}

}

if(flag!=0)

printf("string not found \n");

}

Output:

enter the main string

qwertykeypadkeyboard

enter the pattern

key

string is found at 6

string is found at 12