Lab1&Proj1

Lab/lab00/first_set.txt

@@ -1,4 +1,28 @@
+first_set:
 Which command walks a file hierarchy in search of a keyword?
+find -r [file]
+grep -r [keyword] [directory]
+
 Which command displays information about processes running on your machine?
+jobs只显示当前shell的作业
+ps\top\htop显示进程
+
 Which command terminates a process?
+kill [pid]/pkill [processname]
+
 Which command can help you find the difference between two files?
+diff [file1] [file2]
+
+second set:
+Move files from one directory to the next
+mv [addr1] [addr1]
+Change a file’s permissions
+chmod +x [file]
+Show the directory you’re currently in
+pwd
+Check if a host is online
+ping?
+
+third set:
+Show file permissions for all files in a directory
+ls -la

Lab/lab01/eccentric.c

@@ -1,10 +1,10 @@
 #include <stdio.h>
 
 /* Only change any of these 4 values */
-#define V0 0
-#define V1 -1
-#define V2 0
-#define V3 0
+#define V0 3
+#define V1 3 
+#define V2 1
+#define V3 3
 
 int main(void) {
     int a;
@@ -55,4 +55,4 @@ int main(void) {
     }
 
     return 0;
-}
+}

Lab/lab01/gdb.txt

@@ -1,9 +1,30 @@
-1.
-2.
-3.
-4.
-5.
-6.
-7.
-8.
-9.
+1.While you’re in a gdb session, how do you set the arguments that will be passed to the program when it’s run?
+before run the program, input "set args arg1 arg2 ..."
+
+2.How do you create a breakpoint?
+break [funName/line_number]
+
+3.How do you execute the next line of C code in the program after stopping at a breakpoint?
+next
+
+4.If the next line of code is a function call, you’ll execute the whole function 
+call at once if you use your answer to # (If not, consider a different command for #3!) 
+How do you tell GDB that you want to debug the code inside the function 
+(i.e. step into the function) instead? (If you changed your answer to #3, 
+then that answer is most likely now applicable here.)
+step
+
+5.How do you continue the program after stopping at a breakpoint?
+continue/next
+
+6.How can you print the value of a variable (or even an expression like 1+2) in gdb?
+display 会在每次step显示变量，而print只是打印一次
+
+7.How do you configure gdb so it displays the value of a variable after every step?
+display
+
+8.How do you show a list of all variables and their values in the current function?
+info locals
+
+9.How do you quit out of gdb?
+q

Lab/lab01/hello.c

@@ -11,4 +11,5 @@ int main(int argc, char *argv[]) {
 
     printf("Thanks for waddling through this program. Have a nice day.");
     return 0;
-}
+}
+

Lab/lab01/input.txt

@@ -0,0 +1 @@
+Gingko

Lab/lab01/interactive_hello.c

@@ -10,4 +10,4 @@ int main(int argc, char *argv[]) {
     printf("Hey, %sI just really wanted to say hello to you.\nI hope you have a wonderful day.", a_word);
 
     return 0;
-}
+}

Lab/lab01/ll_cycle.c

@@ -3,5 +3,22 @@
 
 int ll_has_cycle(node *head) {
     /* your code here */
-    return 0;
-}
+    node* tortoise=head,*hare=head;
+    int is_cyclic=0;
+	while(hare!=NULL)
+	{
+		hare=hare->next;
+		if(NULL==hare)
+			break;
+
+		hare=hare->next;
+		tortoise=tortoise->next;
+
+		if(hare==tortoise)
+		{
+			is_cyclic=1;
+			break;
+		}
+	}
+    return is_cyclic;
+}

Project/proj1/imageloader.c

@@ -19,23 +19,83 @@
 #include <inttypes.h>
 #include <string.h>
 #include "imageloader.h"
+#define DEBUG
 
 //Opens a .ppm P3 image file, and constructs an Image object. 
 //You may find the function fscanf useful.
 //Make sure that you close the file with fclose before returning.
+
+char buf[100];
 Image *readData(char *filename) 
 {
-	//YOUR CODE HERE
+	Image* img=(Image*)malloc(sizeof(Image)); 
+	int scale;
+
+	FILE *fp = fopen(filename,"r");
+	if(!fp){
+	    perror("fopen failed");
+	    free(img);
+	    return NULL;
+	}
+
+	fscanf(fp,"%s",buf);
+	fscanf(fp,"%" SCNu32 " %" SCNu32 ,&img->cols,&img->rows);
+	fscanf(fp,"%" SCNu8 ,&scale);
+
+	img->image=(Color**)malloc(sizeof(Color*)*(img->rows));
+
+#ifdef DEBUG
+	printf("width=%d,height=%d,scale=%d\n",img->cols,img->rows,scale);
+#endif
+
+	// start reading pixels 
+	for(int i=0;i<img->rows;i++)
+	{
+		img->image[i]=(Color*)malloc(sizeof(Color)*(img->cols));
+		for(int j=0;j<img->cols;j++)
+		{
+			fscanf(fp,"%" SCNu8 " %" SCNu8 " %" SCNu8 ,
+									&img->image[i][j].R, \
+									&img->image[i][j].G, \
+									&img->image[i][j].B);
+		}	 
+	}
+
+	fclose(fp);
+	return img;
 }
 
 //Given an image, prints to stdout (e.g. with printf) a .ppm P3 file with the image's data.
 void writeData(Image *image)
 {
-	//YOUR CODE HERE
+	printf("P3\n");
+	printf("%"PRIu32" %"PRIu32"\n",image->cols,image->rows);
+	printf("255\n");
+	for(int i=0;i<image->rows;i++)
+	{
+		for(int j=0;j<image->cols;j++)
+		{
+			printf("%3" PRIu8" %3" PRIu8 " %3" PRIu8 ,
+									image->image[i][j].R, \
+									image->image[i][j].G, \
+									image->image[i][j].B);
+			fflush(stdout);
+			if(j!=image->cols-1)
+				printf("   ");
+		}
+		printf("\n");
+	}
+
+	return;
 }
 
 //Frees an image
 void freeImage(Image *image)
 {
-	//YOUR CODE HERE
-}
+	for(int i=0;i<image->rows;i++)
+		free(image->image[i]);		
+
+	free(image->image);
+	free(image);
+	return ;
+}

Project/proj1/imageloadertester.c

@@ -35,4 +35,4 @@ int main(int argc, char **argv)
 	image = readData(filename);
 	writeData(image);
 	freeImage(image);
-}
+}

Project/proj1/steganography.c

@@ -21,13 +21,60 @@
 //Determines what color the cell at the given row/col should be. This should not affect Image, and should allocate space for a new Color.
 Color *evaluateOnePixel(Image *image, int row, int col)
 {
-	//YOUR CODE HERE
+    Color *newColor = (Color *)malloc(sizeof(Color));
+    if (newColor == NULL) {
+        return NULL; 
+    }
+	uint8_t bp = (image->image[row][col].B & 1) ? 0xFF : 0x00;
+	newColor->R=bp;
+	newColor->G=bp;
+    newColor->B=bp;
+	return newColor;
 }
 
 //Given an image, creates a new image extracting the LSB of the B channel.
 Image *steganography(Image *image)
 {
-	//YOUR CODE HERE
+	Image* img=malloc(sizeof(Image));
+	if(NULL==img){
+		return NULL;
+	}
+
+	int cols=image->cols,rows=image->rows;
+	img->image=malloc(rows*sizeof(void*));	
+	if(NULL==img->image){
+        free(img);
+		return NULL;
+	}
+	img->cols=cols,img->rows=rows;	
+	for(int i=0;i<rows;i++)
+	{
+		img->image[i]=malloc(sizeof(Color)*cols);	
+		if(NULL==img->image[i]){
+		    for (int k = 0; k <= i; k++) {
+                free(img->image[k]);
+            }
+            free(img->image);
+        	free(img);
+			return NULL;
+		}
+		for(int j=0;j<cols;j++)
+		{
+			Color *nC=evaluateOnePixel(image,i,j);
+			if(NULL==nC){
+				for (int k = 0; k <= i; k++) 
+                    free(img->image[k]);
+                free(img->image);
+        		free(img);
+				return NULL;
+			}
+			img->image[i][j].R=nC->R;
+			img->image[i][j].G=nC->G;
+			img->image[i][j].B=nC->B;
+			free(nC);
+		}
+	}
+	return img;
 }
 
 /*
@@ -45,5 +92,19 @@ Make sure to free all memory before returning!
 */
 int main(int argc, char **argv)
 {
-	//YOUR CODE HERE
+	if(argc!=2){
+		printf("usage: %s filename\n",argv[0]);
+		printf("filename is an ASCII PPM file (type P3) with maximum value 255.\n");
+		return -1;
+	}
+
+	char*filename=argv[1];
+
+	Image* ppm=readData(filename);
+	Image* hidden_ppm=steganography(ppm);
+	writeData(hidden_ppm);
+	freeImage(hidden_ppm);
+	freeImage(ppm);
+
+	return 0;
 }