Untitled

    int len = strlen(sub);
    int i, j;
    for (i = 0; str[i] != '\0'; i++) {
        for (j = 0; j < len && str[i+j] == sub[j]; j++);
        if (j == len) {
            for (j = 0; str[i+len+j] != '\0'; j++) {
                str[i+j] = str[i+len+j];
            }
            str[i+j] = '\0';
            i--;
        }
    }
}