C++：转换 Win32 文本框 char -> int -> char 并放回另一个文本框

Question

I want to accept text input using a text box, then change the characters to integers and do fun math with my integers, and then put them back into a char array to be printed in another text box.

Here is my code:

int len = GetWindowTextLength(textbox) + 1;
char* text = new char[len];
GetWindowText(textbox, &text[0], len);

int x = 0;
int INTmessage[len];
int ENClen = (len * 2);
char ENCmessage[ENClen];

while (x < len) {
    INTmessage[x] = int(text[x]) - 32;
    x++;
}

int z = 0;
int y = 0;

while (z < ENClen) {
    ENCmessage[z] = (INTmessage[y] % 9);
    ENCmessage[z + 1] = (INTmessage[y] % 10);

    z += 2;
    y++;
}

SetWindowText(textreturn, "");
SetWindowText(textreturn, ENCmessage[0]);

The last line displays a compiler error:

invalid conversion from 'char' to LPCSTR.

Answer 1

Please specify What you mean by 'I don't know why this does not work'. One Error in your code is this:

//This line is incorrect because it converts an address to integer, which has no relation to value of textbox, making decryption impossible.
INTmessage[x] = int(&text[x]) - 32;
//Maybe you may want to use this code: 
INTmessage[x] = int(text[x]) - 32;

Answer 2

The last line fails because you are passing a single char to SetWindowText() (accessing ENCmessage[0] returns the first char in the ENCmessage array). SetWindowText() expects a char* pointer to a null-terminated string instead. You can drop the [0] :

SetWindowText(textreturn, ENCmessage);

Just make sure that ENCmessage contains a null character after your digit characters.

That being said, your code can be re-written to something more like this:

int len = GetWindowTextLength(textbox) + 1;
char* text = new char[len];
len = GetWindowText(textbox, text, len);

int *INTmessage = new int[len];
for(int x = 0; x < len; ++x) {
    INTmessage[x] = int(text[x]) - 32;
}

int ENClen = (len * 2) + 1;
char *ENCmessage = new char[ENClen];

for(int x = 0, y = 0; x < len; ++x, y += 2) {
    ENCmessage[y] = (INTmessage[x] % 9);
    ENCmessage[y + 1] = (INTmessage[x] % 10);
}
ENCmessage[ENCLen-1] = '\0';

SetWindowText(textreturn, ENCmessage);

delete[] INTmessage;
delete[] ENCmessage;
delete[] text;

Or, since you tagged the question as C++, like this instead:

#include <string>
#include <vector>

int len = GetWindowTextLength(textbox) + 1;
std::string text;
text.resize(len);
len = GetWindowText(textbox, &text[0], len);

std::vector<int> INTmessage(len);

for(int x = 0; x < len; ++x) {
    INTmessage[x] = int(text[x]) - 32;
}

int ENClen = (len * 2);
std::string ENCmessage;
ENCmessage.resize(ENClen);

for (int x = 0; y = 0; x < len; ++x, y += 2) {
    ENCmessage[y] = (INTmessage[x] % 9);
    ENCmessage[y + 1] = (INTmessage[x] % 10);
}

SetWindowText(textreturn, ENCmessage.c_str());