String Search Algorithm in C

This is a C Program to perform string matching without using any specific library functions. A text and a pattern is given as input. The pattern is searched for in the text and all instances of the pattern are given as output.

Here is source code of the C Program to Implement the String Search Algorithm for Short Text Sizes. The C program is successfully compiled and run on a Linux system. The program output is also shown below.

```
#include<stdio.h>
```
```
#include<string.h>
```
```
 
```
```
int main() {
```
```
    char org[100], dup[100];
```
```
    int i, j, k = 0, len_org, len_dup;
```

    printf("NOTE:Strings are accepted only till blank space.");

```
    printf("\nEnter Original String:");
```
```
    fflush(stdin);
```
```
    scanf("%s", &org);
```
```
    fflush(stdin);
```
```
    printf("Enter Pattern to Search:");
```
```
    scanf("%s", &dup);
```
```
 
```
```
    len_org = strlen(org);
```
```
    len_dup = strlen(dup);
```

    for (i = 0; i <= (len_org - len_dup); i++) {

```
        for (j = 0; j < len_dup; j++) {
```

            //cout<<"comparing '"<<org[i + j]<<"' and '"<<dup[j]<<"'.";

```
            if (org[i + j] != dup[j])
```
```
                break;
```
```
        }
```
```
        if (j == len_dup) {
```
```
            k++;
```

            printf("\nPattern Found at Position: %d", i);

```
        }
```
```
    }
```
```
    if (k == 0)
```

        printf("\nError:No Match Found!");

```
    else
```

        printf("\nTotal Instances Found = %d", k);

```
    return 0;
```
```
}
```

Output:

$ gcc StringSearch.c
$ ./a.out 
 
NOTE:Strings are accepted only till blank space.
Enter Original String: Stringsareacceptedonlytillblankspace.
Enter Pattern to Search: till
Pattern Found at Position: 22
Total Instances Found = 1

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