no suitable constructor exists to convert from "block [0]" to "block"

I'm trying to return a list ant set a list to SCR_StrPack() but it gives me two errors

#include <iostream>
#include <windows.h>
using namespace std;
int SCR_X = 40;
int SCR_Y = 110;
struct block {
    char DISPLAY = ' ';
    int TYPE = 0;
    float DESTRUCTION = 1.0f;
};
void SCR_Gen(block blck[]) {
    for(int i=0; i<sizeof(blck); i++) {
        cout << blck[i].DISPLAY;
    }
}
block SCR_StrPack(const char STR[]) {
    block blocks[] = {};
    for(int i=0; i<sizeof(STR); i++) {
        blocks[i].DISPLAY = STR[i];
    }
    return blocks;
}
int main() {
    block tr[20] = {};
    tr = SCR_StrPack("\"\"aaa\"\"");
    SCR_Gen(tr);
    return 0;
}

I'm thinking about using for loop but it's one-time use. I don't want to re-type it every time just to mass-modify something in the list.

You can't return arrays and you can't do sizeof(STR) to get the length of a string literal. When passed to the function, the string literal decays into a pointer to the first element, so sizeof(STR) will always be the size of that pointer.

You could use a std::vector<block> to store your blocks instead and you could also use a std::string_view to get the string literals size.

Example:

#include <iostream>
#include <string_view>
#include <vector>

struct block {
    char DISPLAY = ' ';
    int TYPE = 0;
    float DESTRUCTION = 1.0f;
};

void SCR_Gen(const std::vector<block>& blck) {
    for (std::size_t i = 0; i < blck.size(); i++) {
        std::cout << blck[i].DISPLAY;
    }
}

std::vector<block> SCR_StrPack(std::string_view STR) {
    std::vector<block> blocks(STR.size());
    for (std::size_t i = 0; i < STR.size(); i++) {
        blocks[i].DISPLAY = STR[i];
    }
    return blocks;
}

int main() {
    // using a raw string literal is simpler than adding a lot of backslashes:
    auto tr = SCR_StrPack(R"(""aaa"")");
    SCR_Gen(tr);
    return 0;
}

You could also use range based for-loops. Example:

void SCR_Gen(const std::vector<block>& blck) {
    for(auto& blk : blck) {
        std::cout << blk.DISPLAY;
    }
}