Solution for 5_8

c++/Chapter 5/Question5_8.cpp

@@ -1,9 +1,53 @@
 #include<iostream>
 using namespace std;
 
+void PrintScreen(unsigned char buffer[], int width, int height){
+    int byteWidth = width / 8;
+    for(int row = 0; row < height; ++row){
+        for(int column = 0; column < byteWidth; ++column){
+            int index = row * byteWidth + column;
+            char block = buffer[index];
+            for(int i = 7; i >= 0; --i){
+                if( (block >> i) & 1){
+                    cout << '.';
+                }
+                else{
+                    cout << ' ';
+                }
+            }
+        }
+        cout << '\n';
+    }
+}
 
+void SetBit(unsigned char& byte, int bit){
+    byte |= 1 << bit;
+}
 
-int main(){
+void DrawHorizontalLine(unsigned char buffer[], int bufferLength, int width, int x1, int x2, int y){
+    int x = width * y + x1;
+    int end = width * y + x2;
+    while(x < end){
+        int byteIndex = x / 8;
+        int bit = x - byteIndex * 8;
+        SetBit(buffer[byteIndex], 7 - bit);
+        ++x;
+    }
+}
 
+int main(){
+    unsigned char screen[] = {
+        0x80, 0x01,
+        0x40, 0x02,
+        0x20, 0x04,
+        0x10, 0x08,
+        0x08, 0x10,
+        0x04, 0x20,
+        0x02, 0x40,
+        0x01, 0x80
+    };
+    PrintScreen(screen, 16, 8);
+    DrawHorizontalLine(screen, 2 * 8, 16, 5, 9, 2);
+    PrintScreen(screen, 16, 8);
 	return 0;
 }