系统编程文件部分

Chapter13/io/stdio/atoi.c

@@ -0,0 +1,28 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(int argc, char **argv)
+{
+    char buf[1024];
+    int  year = 2014, month = 5, day = 13;
+
+    printf("%d-%d-%d\n", year, month, day);
+
+    sprintf(buf, "%d-%d-%d", year, month, day);
+    puts(buf);
+
+#if 0
+    char str[] = "123456";
+
+    printf("%d\n", atoi(str));
+    /**
+     * 输出 123456
+     * 
+     * 如果str是123a456
+     * 输出123
+     * 
+     */
+#endif
+
+    exit(0);
+}

Chapter13/io/stdio/fflush.c

@@ -0,0 +1,20 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(int argc, char **argv)
+{
+    int i;
+
+    // 这里不加\n的话，什么都不输出
+    // 要么加\n，要么fflush
+    printf("Before while()");
+    fflush(stdout);
+
+    while (1)
+        ;
+
+    printf("After while()");
+    fflush(NULL);
+
+    exit(0);
+}

Chapter13/io/stdio/fgetc.c

@@ -0,0 +1,32 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(int argc, char **argv)
+{
+    FILE *fp;
+    int   count;
+
+    if (argc < 2)
+    {
+        fprintf(stderr, "Usage...\n");
+        exit(1);
+    }
+
+    fp = fopen(argv[1], "r");
+    if (NULL == fp)
+    {
+        perror("fopen()");
+        exit(1);
+    }
+
+    while (EOF != fgetc(fp))
+    {
+        count++;
+    }
+
+    printf("count = %d", count);
+
+    fclose(fp);
+
+    exit(0);
+}

Chapter13/io/stdio/flen.c

@@ -0,0 +1,28 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(int argc, char **argv)
+{
+    FILE *fp;
+
+    if (argc < 2)
+    {
+        fprintf(stderr, "Usage...\n");
+        exit(1);
+    }
+
+    fp = fopen(argv[1], "r");
+    if (NULL == fp)
+    {
+        perror("fopen()");
+        exit(1);
+    }
+
+    fseek(fp, 0, SEEK_END);
+
+    printf("%d\n", ftell(fp));
+
+    fclose(fp);
+
+    exit(0);
+}

Chapter13/io/stdio/fopen.c

@@ -25,5 +25,7 @@ int main()
 
     puts("OK!");
 
+    fclose(fp);
+
     exit(0);
 }

Chapter13/io/stdio/maxfopen.c

@@ -0,0 +1,32 @@
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+int main()
+{
+    FILE *fp    = NULL;
+    int   count = 0;
+
+
+    while (1)
+    {
+
+        fp = fopen("tmp", "w");
+        if (NULL == fp)
+        {
+            perror("fopen()");
+            break;
+        }
+
+        count++;
+    }
+
+    printf("count = %d\n", count);
+    // out: 4089
+    /* 可以通过下面这个命令限制 */
+    /* ulimit -n */
+    /* 4096 */
+
+    exit(0);
+}

Chapter13/io/stdio/mycpy.c

@@ -0,0 +1,51 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+/**
+ * @brief
+ * @details
+ *          usage: ./mycpy <src> <dst>
+ *
+ * @return  int
+ */
+
+int main(int argc, char **argv)
+{
+    FILE *fps, *fpd;
+    int   ch;
+
+    if (argc < 3)
+    {
+        fprintf(stderr, "Usage:%s <src> <dst>\n", argv[0]);
+        exit(1);
+    }
+
+    fopen(argv[1], "r");
+    if (NULL == fps)
+    {
+        perror("fopen()");
+        exit(1);
+    }
+
+    fopen(argv[2], "w");
+    if (NULL == fpd)
+    {
+        // !!!
+        fclose(fps);
+        perror("fopen()");
+        exit(1);
+    }
+
+    while (1)
+    {
+        ch = fgetc(fps);
+        if (EOF == ch)
+            break;
+        fputc(ch, fpd);
+    }
+
+    fclose(fpd);
+    fclose(fps);
+
+    exit(0);
+}

Chapter13/io/stdio/mycpy_fgets.c

@@ -0,0 +1,48 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+#define BUFSIZE 1024
+
+/**
+ * @brief
+ * @details
+ *          usage: ./mycpy <src> <dst>
+ *
+ * @return  int
+ */
+
+int main(int argc, char **argv)
+{
+    FILE *fps, *fpd;
+    char  buf[BUFSIZE];
+
+    if (argc < 3)
+    {
+        fprintf(stderr, "Usage:%s <src> <dst>\n", argv[0]);
+        exit(1);
+    }
+
+    fopen(argv[1], "r");
+    if (NULL == fps)
+    {
+        perror("fopen()");
+        exit(1);
+    }
+
+    fopen(argv[2], "w");
+    if (NULL == fpd)
+    {
+        // !!!
+        fclose(fps);
+        perror("fopen()");
+        exit(1);
+    }
+
+    while (NULL != fgets(buf, BUFSIZE, fps))
+        fputs(buf, fpd);
+
+    fclose(fpd);
+    fclose(fps);
+
+    exit(0);
+}

Chapter13/io/stdio/mycpy_fread.c

@@ -0,0 +1,50 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+#define BUFSIZE 1024
+
+/**
+ * @brief
+ * @details
+ *          usage: ./mycpy <src> <dst>
+ *
+ * @return  int
+ */
+
+int main(int argc, char **argv)
+{
+    FILE *fps, *fpd;
+    char  buf[BUFSIZE];
+    int   n;
+
+    if (argc < 3)
+    {
+        fprintf(stderr, "Usage:%s <src> <dst>\n", argv[0]);
+        exit(1);
+    }
+
+    fopen(argv[1], "r");
+    if (NULL == fps)
+    {
+        perror("fopen()");
+        exit(1);
+    }
+
+    fopen(argv[2], "w");
+    if (NULL == fpd)
+    {
+        // !!!
+        fclose(fps);
+        perror("fopen()");
+        exit(1);
+    }
+
+    /* 用n接收读到的个数，因为不知道能不能正好读到BUFSIZE */
+    while ((n = fread(buf, 1, BUFSIZE, fps)) > 0)
+        fread(buf, 1, n, fpd);
+
+    fclose(fpd);
+    fclose(fps);
+
+    exit(0);
+}