diff --git a/strops.c b/strops.c
index e88802c..2345131 100644
--- a/strops.c
+++ b/strops.c
@@ -1,8 +1,6 @@
 #include "strops.h"
-#include <string.h>
 #include <stdlib.h>
 #include <assert.h>
-
 #include <stdio.h>
 
 /* Function template
@@ -62,9 +60,35 @@ char* strops_copy_amount(const char* string, ull_t amount) {
     return result;
 }
 
+ull_t strops_first_pos_of_char(const char* string, char char_to_search) {
+    ull_t i;
+    for (i = 0; string[i] != char_to_search; i++) {}
+    return i;
+}
+
+ull_t strops_first_pos_of_string(const char* string, const char* string_to_search) {
+    char contains_string;
+    ull_t sts_length = strops_length(string_to_search);
+    ull_t l = strops_length(string) - sts_length + 1;
+    ull_t i, j;
+    for (i = 0; i < l; i++) {
+        contains_string = 1;
+        for(j = 0; j < sts_length; j++) {
+            if (string[i + j] != string_to_search[j]) {
+                contains_string = 0;
+                break;
+            }
+        }
+        if (contains_string) {
+            break;
+        }
+    }
+    return i;
+}
+
 char strops_contains_char(const char* string, char char_to_search) {
     ull_t i;
-    for (i = 0; i < strops_length(string); i++) {
+    for (i = 0; i < strops_length(string) + 1; i++) {
         if (string[i] == char_to_search) {
             return 1;
         }
@@ -173,7 +197,7 @@ char* strops_replace_at_pos_string(const char* string, const char* string_to_rem
 
 char* strops_trim_right_whitespace(const char* string) {
     char* result = strops_copy(string);
-    while (strchr("\t\n\v\f\r ", result[strops_length(result) - 1]) != NULL) {
+    while (strops_contains_char("\t\n\v\f\r ", result[strops_length(result) - 1])) {
         result = strops_remove_at_pos_char(result, strops_length(result) - 1);
     }
     result = realloc(result, strops_length(result));
@@ -182,7 +206,7 @@ char* strops_trim_right_whitespace(const char* string) {
 
 char* strops_trim_left_whitespace(const char* string) {
     char* result = strops_copy(string);
-    while (strchr("\t\n\v\f\r ", result[0]) != NULL) {
+    while (strops_contains_char("\t\n\v\f\r ", result[0])) {
         result = strops_remove_at_pos_char(result, 0);
     }
     result = realloc(result, strops_length(result));
@@ -200,7 +224,7 @@ char* strops_trim_both_whitespace(const char* string) {
 
 char* strops_trim_right_chars(const char* string, const char* chars_to_remove) {
     char* result = strops_copy(string);
-    while (strchr(chars_to_remove, result[strops_length(result) - 1]) != NULL) {
+    while (strops_contains_char(chars_to_remove, result[strops_length(result) - 1])) {
         result = strops_remove_at_pos_char(result, strops_length(result) - 1);
     }
     result = realloc(result, strops_length(result));
@@ -209,7 +233,7 @@ char* strops_trim_right_chars(const char* string, const char* chars_to_remove) {
 
 char* strops_trim_left_chars(const char* string, const char* chars_to_remove) {
     char* result = strops_copy(string);
-    while (strchr(chars_to_remove, result[0]) != NULL) {
+    while (strops_contains_char(chars_to_remove, result[0])) {
         result = strops_remove_at_pos_char(result, 0);
     }
     result = realloc(result, strops_length(result));
@@ -272,10 +296,10 @@ char* strops_trim_both_string(const char* string, const char* string_to_remove)
 char* strops_remove_chars(const char* string, const char* chars_to_remove) {
     char* result = strops_copy(string);
 
-    ull_t i;
+    ull_t i, j;
     for (i = 0; i < strops_length(chars_to_remove); i++) {
-        while (strchr(result, chars_to_remove[i]) != NULL) {
-            result = strops_remove_at_pos_char(result, strops_length(result) - strops_length(strchr(result, chars_to_remove[i])));
+        while (strops_contains_char(result, chars_to_remove[i])) {
+            result = strops_remove_at_pos_char(result, strops_first_pos_of_char(result, chars_to_remove[i]));
         }
     }
     result = realloc(result, strops_length(result));
@@ -286,8 +310,8 @@ char* strops_remove_string(const char* string, const char* string_to_remove) {
     assert(strops_length(string) >= strops_length(string_to_remove) && "string_to_remove cannot be bigger than string");
     char* result = strops_copy(string);
 
-    while (strstr(result, string_to_remove) != NULL) {
-        ull_t offset = strops_length(result) - strops_length(strstr(result, string_to_remove));
+    while (strops_contains_string(result, string_to_remove)) {
+        ull_t offset = strops_first_pos_of_string(result, string_to_remove);
         ull_t i;
         for (i = 0; i < strops_length(string_to_remove); i++) {
             result  = strops_remove_at_pos_char(result, offset);
@@ -303,35 +327,32 @@ ull_t strops_word_count(const char* string) {
 
     ull_t i = 0;
     ull_t beginning_of_word = 0;
-    ull_t end_of_word = end_of_word;
     while (i < strops_length(string) - 1) {
-        for (; i < strops_length(string); i++) {
+        for (; i < strops_length(tmp); i++) {
             if ((tmp[i] >= 'A' && tmp[i] <= 'Z') || (tmp[i] >= 'a' && tmp[i] <= 'z')) {
                 beginning_of_word = i;
                 break;
             }
         }
 
-        if (strchr("\t\n\v\f\r ", tmp[beginning_of_word - 1]) == NULL) {
+        if (!strops_contains_char("\t\n\v\f\r ", tmp[beginning_of_word - 1])) {
             continue;
         }
 
-        for (i = beginning_of_word; i < strops_length(string); i++) {
+        for (i = beginning_of_word; i < strops_length(tmp); i++) {
             if (!(tmp[i] >= 'A' && tmp[i] <= 'Z') && !(tmp[i] >= 'a' && tmp[i] <= 'z')) {
-                end_of_word = i;
                 break;
             }
         }
 
-        if (strchr("\t\n\v\f\r ", tmp[end_of_word + 1]) == NULL) {
+        if (!strops_contains_char("\t\n\v\f\r ", tmp[i + 1])) {
             continue;
         }
 
-        if (end_of_word - beginning_of_word < 2) {
+        if (i - beginning_of_word < 2) {
             continue;
         }
         
-        i = end_of_word;
         word_count++;
     }
     free(tmp);
@@ -340,7 +361,7 @@ ull_t strops_word_count(const char* string) {
 
 /* TODO: verify that this is correct */
 int strops_is_url_encoded(const char* string) {
-    if (strchr(string, '%') != NULL) {
+    if (strops_contains_char(string, '%')) {
         return 1;
     }
     return 0;
@@ -358,7 +379,7 @@ char* strops_url_encode(const char* string) {
     ull_t i, j;
     for (i = 0; i < strops_length(unsafe_chars); i++) {
         j = 0;
-        while (strchr(result, unsafe_chars[i]) != NULL) {
+        while (strops_contains_char(result, unsafe_chars[i])) {
             if (result[j] == unsafe_chars[i]) {
                 char bad = result[j];
                 sprintf(replacement + 1, "%02X", bad);