C Function To Replace char In String

I have written function to replace a particular char from a string
Eg. removes junk char from string and returns valid string
eg. input string as my+comments
output will be my comments
It returns the pointer to updated string

here we go..

char *replace_char_in_string(char *string, char to_search, char to_replace_with)
{
char *buf;
int i=0,j=0;
char temp[1024];

while(string[i] !='\0')
{
if(string[i] == to_search )
{
temp[j] = to_replace_with;
i++;
j++;
}
else
temp[j++] = string[i++];
}
temp[j] = '\0';
buf = (char *) malloc(strlen(temp) + 1);
strcpy(buf,temp);
// printf("%s\n",buf);
return buf;
}

Enjoy.
Is there any better way to do this. please do comment.