added a few and minor syntax changes

Lec1/.gitignore

+*~
+*.out

Lec1/array.c

+int main(void)
+{
+
+    double y[10];
+    double x;
+
+    y[0] = 3.1415926;
+    y[1] = 2.71828;
+    y[2] = 0;
+    y[10] = 666;
+
+}

Lec1/eighth.c

@@ -9,6 +9,6 @@ int main(int argc, char* argv[]) {
 	printf("pi= %f\n\n", pi);
 
 	for (i=0; i<4; i++) {
-		printf("pf[%d]= %x\n", i, pf[i]);
+		printf("pf[%d]= %02hhx\n", i, pf[i]);
 	}
 }

Lec1/first.c

 #include <stdio.h>
+#include <stdlib.h>
 
-int main(int argc, char* argv[]) {
-	printf("hello C world\n");
+int main(int argc, char* argv[])
+{
+    printf("hello C world\n");    // from stdio.h
+    return EXIT_SUCCESS;          // from stdlib.h
 }
+
+

Lec1/scanf.c

+#include <stdio.h>
+
+int main(void){
+    int   i;
+    float x;
+    char text[80];
+
+    scanf("%d", &i);
+    scanf("%f", &x);
+    scanf("%s", text);
+    printf(" i= %d\n", i);
+    printf(" x= %f\n", x);
+    printf(" text= %s\n", text);
+}

Lec1/selection.c

+switch (i) {
+case 1:
+	j = -i;
+	break;
+case 2:
+ 	j += 123;
+ 	break;
+case 3:
+	j = 999;
+	break;
+default: {
+		j = 666;
+	}
+	break;
+}

Lec1/sixth.c

@@ -5,8 +5,8 @@ int main(int argc, char* argv[]) {
 	int   i = 7;
 	int   j = -1;
 
-	int*  pi = &i;
-	int*  pj = &j;
+	int *pi = &i;
+	int *pj = &j;
 
 	printf(" i = %d\n", i);
 	printf(" j = %d\n", j);