diff --git a/src/base/cptr.c b/src/base/cptr.c
index 5876d1a..07eee43 100644
--- a/src/base/cptr.c
+++ b/src/base/cptr.c
@@ -189,27 +189,29 @@ char* cptr_toUpper(const char* src) {
     return p;
 }
 
-char* cptr_replaceChar(const char* src, char c_old, char c_new, u32 startIndex, u32 seekLength){
+char* cptr_replaceCharIn(const char* src, char c_old, char c_new, u32 startIndex, u32 seekLength){
     char* rzlt=cptr_copy(src);
-    char c=*src;
-    for(u32 i=startIndex; i<seekLength && c!=0; i++, src++){
-        if(c==c_old)
-            *rzlt=c_new;
+    for(u32 i=startIndex; i!=seekLength && src[i]!=0; i++){
+        if(src[i]==c_old)
+            rzlt[i]=c_new;
     }
     return rzlt;
 }
 
-char* cptr_replace(const char* src, char* str_old, char* str_new, u32 startIndex, u32 seekLength){
+char* cptr_replaceIn(const char* src, const char* str_old, const char* str_new, u32 startIndex, u32 seekLength){
     StringBuilder* sb=StringBuilder_create();
     const u32 str_old_len=cptr_length(str_old);
     const u32 str_new_len=cptr_length(str_new);
     i32 i=startIndex;
-    while( (i=cptr_seek(src, str_old, i, -1)) !=-1 ){
+    while( (i=cptr_seek(src, str_old, startIndex, seekLength)) !=-1 ){
         if(i!=0)
             StringBuilder_append_string(sb, (string){.ptr=(char*)src, .length=i});
         StringBuilder_append_string(sb, (string){.ptr=str_new, .length=str_new_len});
         src+=i+str_old_len;
     }
+    u32 src_remains_len=cptr_length(src);
+    if(src_remains_len>0)
+        StringBuilder_append_string(sb, (string){.ptr=(char*)src, .length=src_remains_len});
     string rezult=StringBuilder_build(sb);
     return rezult.ptr;
 }
diff --git a/src/base/cptr.h b/src/base/cptr.h
index fe15bed..509577c 100644
--- a/src/base/cptr.h
+++ b/src/base/cptr.h
@@ -77,11 +77,17 @@ char* cptr_toUpper(const char* src);
 /// @param startIndex 0 ... src length
 /// @param seekLength 0 ... -1
 /// @return <src> with <str_old> replaced by <str_new> or empty cstring if <str_old> not found
-char* cptr_replace(const char* src, char* str_old, char* str_new, u32 startIndex, u32 seekLength);
+char* cptr_replaceIn(const char* src, const char* str_old, const char* str_new, u32 startIndex, u32 seekLength);
 /// @param startIndex 0 ... src length
 /// @param seekLength 0 ... -1
 /// @return <src> with <c_old> replaced by <c_new> or empty cstring if <str_old> not found
-char* cptr_replaceChar(const char* src, char c_old, char c_new, u32 startIndex, u32 seekLength);
+char* cptr_replaceCharIn(const char* src, char c_old, char c_new, u32 startIndex, u32 seekLength);
+
+static inline char* cptr_replace(const char* src, const char* str_old, const char* str_new)
+{ return cptr_replaceIn(src, str_old, str_new, 0, -1); }
+
+static inline char* cptr_replaceChar(const char* src, char c_old, char c_new)
+{ return cptr_replaceCharIn(src, c_old, c_new, 0, -1); }
 
 #if __cplusplus
 }
diff --git a/tests/test_cptr.c b/tests/test_cptr.c
index ff05f4e..83dfadb 100644
--- a/tests/test_cptr.c
+++ b/tests/test_cptr.c
@@ -1,14 +1,5 @@
 #include "tests.h"
 
-/*
-        TODO
-test cptr_seek...
-test cptr_...indexOf... 
-test cptr_replace...
-
-cases:
-*/
-
 const char* strings[]={
     "",
     "abab",
@@ -70,7 +61,7 @@ const char* strings[]={
 const int strings_len=sizeof(strings)/sizeof(strings[0]);
 
 void test_cptr(){
-    // optime(__func__,1,
+    optime(__func__,1,
         kprintf("\e[96m-------------[test_cptr]--------------\n");
         // compare
         kprintf("\e[94m--------------[compare]---------------\n");
@@ -157,5 +148,7 @@ void test_cptr(){
         test_seekReverse("ab", "", 2, 2, -1)
         test_seekReverse("ab", "b", 1, 2, 1)
         test_seekReverse("ab", "b", 1, 1, 1)
-    // );
+
+        // TODO cptr_replace
+    );
 }
\ No newline at end of file