Replace a character in a string using assembly code in MASM - string

Question

So my program is very simple. I have a string "Hello World" and I want to replace 'H' with 'A'. So here is my assembly code for MASM.
char* name = "Hello World";
_asm
{
mov eax, name;
mov ebx, 'A';
mov [eax], ebx;
}
printf("%s", name);
Visual Studio cannot compile this. It alerts me that this program is not working. I suspect my syntax for mov[eax], ebx might be wrong. All comments are appreciated. Thanks!
Here is the image of the alert: https://www.dropbox.com/s/e5ok96pj0mxi6sa/test%20program%20not%20working.PNG

Answer 1

"Hello World" is a literal, i.e a non-writeable constant string. 'name' is a pointer which points to that literal. You can instead define an array, which has to be populated with that literal, i.e. the literal is copied into the array:
#include <stdio.h>
int main (void)
{
char name[] = "Hello World";
_asm
{
lea eax, name; // EAX = address of name
mov ebx, 'A';
mov [eax], bl;
}
printf("%s", name);
return 0;
}
The original code works, if you use the C89-Compiler of MSVC (file-extension .c or command line option /TC), but that does not really meet the standard.

Answer 2

First Character
mov eax, _name; // EAX = address of name
mov bl, 'A';
mov byte[eax], bl;
Second Character
mov eax, _name; // EAX = address of name
mov bl, 'A';
mov byte[eax+1], bl;
MOVS
MOVS - This instruction moves 1 Byte, Word or Doubleword of data from memory location to another.
LODS
LODS - This instruction loads from memory. If the operand is of one byte, it is loaded into the AL register, if the operand is one word, it is loaded into the AX register and a doubleword is loaded into the EAX register.
STOS
STOS - This instruction stores data from register (AL, AX, or EAX) to memory.
CMPS
CMPS - This instruction compares two data items in memory. Data could be of a byte size, word or doubleword.
SCAS
SCAS - This instruction compares the contents of a register (AL, AX or EAX) with the contents of an item in memory.