[SP/P01] Solved exercises from first practice (again)

5 files changed, 142 insertions, 0 deletions

diff --git a/Year 3/System programming/Practice01/ex1-cp.c b/Year 3/System programming/Practice01/ex1-cp.c
new file mode 100644
index 0000000..ff39983
--- /dev/null
+++ b/Year 3/System programming/Practice01/ex1-cp.c
@@ -0,0 +1,25 @@
+#include <fcntl.h>  // open, close, O_RDONLY, ...
+#include <stdio.h>  // perror
+#include <unistd.h> // read, write
+
+int main(int argc, char* argv[]) {
+	int f1 = open(argv[1], O_RDONLY);
+	if (f1 < 0) {
+		perror("open");
+		return 1;
+	}
+
+	int f2 = open(argv[2], O_WRONLY | O_CREAT | O_TRUNC, 0755);
+	if (f2 < 0) {
+		perror("open");
+		return 2;
+	}
+
+	char buf;
+	while(read(f1, &buf, 1)) {
+		write(f2, &buf, 1);
+	}
+
+	close(f1);
+	close(f2);
+}
diff --git a/Year 3/System programming/Practice01/ex2-head.c b/Year 3/System programming/Practice01/ex2-head.c
new file mode 100644
index 0000000..197e8d2
--- /dev/null
+++ b/Year 3/System programming/Practice01/ex2-head.c
@@ -0,0 +1,21 @@
+#include <unistd.h> // ssize_t, read, write
+#include <fcntl.h> // open, close, O_RDONLY, ...
+#include <stdio.h> // printf, perror
+
+int main(int argc, char* argv[]) {
+	int f = open(argv[1], O_RDONLY);
+	if (f < 0) {
+		perror("open");
+		return 1;
+	}
+
+	ssize_t lines = 10;
+
+	char buf;
+	while (read(f, &buf, 1) && lines > 0) {
+		if (buf == '\n') lines--;
+		printf("%c", buf);
+	}
+
+	close(f);
+}
diff --git a/Year 3/System programming/Practice01/ex3-cmp.c b/Year 3/System programming/Practice01/ex3-cmp.c
new file mode 100644
index 0000000..19bc336
--- /dev/null
+++ b/Year 3/System programming/Practice01/ex3-cmp.c
@@ -0,0 +1,31 @@
+#include <unistd.h> // ssize_t, read, write
+#include <fcntl.h> // open, close, O_RDONLY, ...
+#include <stdio.h> // perror
+
+// exit 0 - equal
+// exit 1 - different
+int main(int argc, char* argv[]) {
+	int f1 = open(argv[1], O_RDONLY);
+	if (f1 < 0) {
+		perror("open");
+		return 2;
+	}
+
+	int f2 = open(argv[2], O_RDONLY);
+	if (f2 < 0) {
+		perror("open");
+		return 3;
+	}
+
+	char buf1, buf2;
+	ssize_t read1, read2;
+	do {
+		read1 = read(f1, &buf1, 1);
+		read2 = read(f2, &buf2, 1);
+		if (buf1 != buf2) return 1;
+	} while (read1 > 0 && read2 > 0);
+	if (read1 != read2) return 1;
+
+	close(f1);
+	close(f2);
+}
diff --git a/Year 3/System programming/Practice01/ex4-wc.c b/Year 3/System programming/Practice01/ex4-wc.c
new file mode 100644
index 0000000..29fb572
--- /dev/null
+++ b/Year 3/System programming/Practice01/ex4-wc.c
@@ -0,0 +1,33 @@
+#include <unistd.h> // read, write
+#include <fcntl.h> // open, close, O_RDONLY
+#include <stdio.h> // printf, perror
+
+int isBlank(char c) {
+	return c == ' ' || c == '\n' || c == '\t';
+}
+
+// print line, word and byte count
+int main(int argc, char* argv[]) {
+	int f = open(argv[1], O_RDONLY);
+	if (f < 0) {
+		perror("open");
+		return 1;
+	}
+
+	int lines = 0, words = 0, bytes = 0;
+	char buf;
+	int lastWasBlank = 0;
+	while (read(f, &buf, 1)) {
+		bytes++;
+		if (buf == '\n') lines++;
+		if (isBlank(buf)) {
+			words += !lastWasBlank;
+			lastWasBlank = 1;
+		}
+		else lastWasBlank = 0;
+	}
+
+	close(f);
+
+	printf("%d %d %d %s\n", lines, words, bytes, argv[1]);
+}
diff --git a/Year 3/System programming/Practice01/ex5-cut.c b/Year 3/System programming/Practice01/ex5-cut.c
new file mode 100644
index 0000000..e1d6bf2
--- /dev/null
+++ b/Year 3/System programming/Practice01/ex5-cut.c
@@ -0,0 +1,32 @@
+#include <fcntl.h> // open, close, O_RDONLY
+#include <stdio.h> // printf, scanf, perror
+#include <unistd.h> // read
+
+// print characters from column m to n (1 indexed) for each row
+int main(int argc, char* argv[]) {
+	int f = open(argv[1], O_RDONLY);
+	if (f < 0) {
+		perror("open");
+		return 1;
+	}
+
+	int m, n;
+	scanf("%d %d", &m, &n);
+
+	int col = 1;
+	char buf;
+	while (read(f, &buf, 1)) {
+		if (buf == '\n') {
+			col = 1;
+			printf("\n");
+			continue;
+		}
+
+		if (m <= col && col <= n) {
+			printf("%c", buf);
+		}
+		col++;
+	}
+
+	close(f);
+}