Go beyond out of range of array index

I wanna write a program, which gets a text at one line (maximum of text lenntgh is 20) and then user enters "end"

after that I ask user number of searchs and ask for words and then i say how many time any words repeated

it is an example output and input:

input:

It’s an example passage.
end
2
it
exam 

Output

it : 1
exam : 1 

this is my code:

#include <stdio.h>
int mystrlen(char *s)
{
    int length = 0;

    while (*s != '\0')
    {
        length++;
        s++;
    }
    return length;
}
void match(char *haystack, char* needle, int d,int ns)
{
    int j = 0;

    int i, counter = 0;

    for (i = 0; i < mystrlen(haystack); i++)
    {

        if (haystack[i] == needle[j])
        {
            if (j == mystrlen(needle) - 1)
            {
                counter++;
                j = 0;
                continue;
            }
        }
        else
        {
            j = 0;
            continue;
        }
        j++;

    }
    if (d < (ns-1))
    {
        printf("%s : %d\n", needle, counter);
    }
    else
    {
        printf("%s : %d", needle, counter);
    }
}
int main()
{
    int i = 0;
    int ro;
    char p;
    char lol[10];
    int ns;
    char c_to_search[10][10];
    char text[25];
    gets(text);
    i = mystrlen(text);
    scanf("%s", &text[i]);
    i = mystrlen(text);
    text[i - 1] = '\0';
    text[i - 2] = '\0';
    text[i - 3] = '\0';
    text[i - 4] = '\0';
    for (i = 0; text[i] != '\0'; ++i)
    {
        if ((text[i]>64) && (text[i]<91))
            text[i] = text[i] + 32;
    }
    scanf("%d", &ns);
    i = 0;
    scanf("%c", &p);
    for (i = 0; i<ns; i++)
    {

        gets(c_to_search[i]);
    }
    for (i = 0; i<ns; ++i)
    {
        for (ro = 0; ro<mystrlen(c_to_search[i]); ++ro)
        {
            if ((c_to_search[i][ro]>64) && (c_to_search[i][ro]<91))
                c_to_search[i][ro] = c_to_search[i][ro] + 32;

        }
    }
    i = 0;
    for (i; i<ns; ++i)
    {
        match(text, c_to_search[i],i,ns);
    }
}

It works well but my problem is that sometimes the array index ranges are forgot and it causes Run time Error

Would you mind helping me how to fix that?