Delete all occurrences of pattern from a string

Delete all occurrences of pattern (pat) from a string (txt)

#include<stdio.h>

#include<string.h>

void main()

{

                char txt[30],  pat[30];

                int m, n;

                int i, j, found = 0;

                printf("\nEnter the main string:");

                gets(txt);

                printf("\nEnter the pattern to be searched: ");

                gets(pat);

                m = strlen(txt);

                n = strlen(pat);

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

                {

                                found  = 1;

                                for(j=0; j<n; j++)

                                {

                                                if(txt[i+j] != pat[j])

                                                {

                                                                found = 0;

                                                                break;

                                                }

                                }

                                if(found == 1)

                                {

                    /* If pattern is found then shift all characters to left and decrement the string length */

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

                                                {

                                                                txt[j] = txt[j+n];

                                                }

                                                txt[j] = '\0';

                                                m = m - n;

                                 }

                }

                if(found == 0)

                                printf("\nPattern not found");

                else

                {

                                printf("\nAfter deleting pattern the string is: ");

                                puts(txt);

                }

}

Output:

Enter the main string:    hello hii how hii

Enter the pattern to be searched:   hii

After deleting pattern the string is: hello    how

Enter the main string:    hello hii how hii

Enter the pattern to be searched: abc

Pattern not found