20130426

How to search a substring in C++/Cpp without using library function strstr


/*How to search a sub string without using library function strstr. 
How to use pointer/array to search substring in a string sentence.
C++/CPP/C program/code to search a word in a sentence without using inbuilt function strstr*/
#include<stdio.h>
#include<string.h>
int main()
{
char arr1[50];
printf("Enter a String:\n");
scanf("%s",&arr1);

char arr2[20];
printf("Enter a String:\n");
scanf("%s",&arr2);
printf("Searching for:%s\n",arr2);

int count1, count2;
count1=0; count2=0;
while(arr1[count1]!='\0')
count1++;
while(arr2[count2]!='\0')
count2++;
int i,j,flag;
for(i=0;i<count1-count2;i++)
{
for(j=i;j<i+count2;j++)
{
flag=1;
if(arr1[j]!=arr2[j-i])
{
flag=0;
break;
}
}
if (flag==1)
break;
}
if (flag==1)
printf("yes found\n");
else
printf("Not found\n");
return 0;
}/*
Enter a String:
zxcvbnaaaSONYdkjsdfklj
Enter a String:
SONY
Searching for:SONY
yes found*/
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1 comment:

  1. Example: Builtin function strstr to find a substring in a string:

    strstr function searches first occurrence of the substring(here word for cpp) in main string(here sentence howtocpp.com) and returns the pointer to the first char.
    #include
    using namespace std;
    #include
    int main main()
    {
    char sentence[]="howtocpp.com";
    char word[]="cpp";
    char *ptr;
    ptr=strstr(sentence, word);
    cout<<"The Substring is :"<<ptr;
    return 0;
    }
    //This will output into
    //The Substring is:cpp

    ReplyDelete