完成了表达式计算小程序

Chapter11/ds/line/compute/Makefile

@@ -0,0 +1,31 @@
+# 方便起见一般都会先定义编译器链接器
+CC = gcc 
+LD = gcc
+
+# 正则表达式表示目录下所有.c文件，相当于：SRCS = main.c a.c b.c
+SRCS = $(wildcard *.c)
+
+# OBJS表示SRCS中把列表中的.c全部替换为.o，相当于：OBJS = main.o a.o b.o
+OBJS = $(patsubst %c, %o, $(SRCS))
+
+# 可执行文件的名字
+TARGET = main
+
+# .PHONE伪目标，具体含义百度一下一大堆介绍
+.PHONY:all clean
+
+# 要生成的目标文件
+all: $(TARGET)
+
+# 第一行依赖关系：冒号后面为依赖的文件，相当于Hello: main.o a.o b.o
+# 第二行规则：$@表示目标文件，$^表示所有依赖文件，$<表示第一个依赖文件
+$(TARGET): $(OBJS)
+	$(LD) -o $@ $^
+
+# 上一句目标文件依赖一大堆.o文件，这句表示所有.o都由相应名字的.c文件自动生成
+%.o:%.c
+	$(CC) -c $^
+
+# make clean删除所有.o和目标文件
+clean:
+	rm -f $(OBJS) $(TARGET)

Chapter11/ds/line/compute/main.c

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+#include <stdio.h>
+#include <stdlib.h>
+
+#include "sqstack.h"
+
+// !!! 课程不完整，程序未写完
+// TODO: snum和sop需要不同的datatype
+
+static void compute(sqstack *snum, int *op)
+{
+    datatype n1, n2, n;
+
+    st_pop(snum, &n2);
+    st_pop(snum, &n1);
+
+    switch (*op)
+    {
+    case '+': n = n1 + n2; break;
+    case '-': n = n1 - n2; break;
+    case '*': n = n1 * n2; break;
+    case '/': n = n1 / n2; break;
+
+    default: exit(1);
+    }
+    st_push(snum, &n);
+}
+
+static deal_bracket(sqstack *snum, sqstack *sop)
+{
+    datatype old_op;
+
+    st_top(sop, &old_op);
+
+    while (old_op != '(')
+    {
+        st_pop(sop, &old_op);
+        compute(snum, &old_op);
+        st_top(sop, &old_op);
+    }
+
+    st_pop(sop, &old_op);
+}
+
+static int get_pri(int op)
+{
+    switch (op)
+    {
+    case '(': return 0;
+    case '+':
+    case '-': return 1;
+    case '*':
+    case '/': return 2;
+    }
+}
+
+
+static void deal_op(sqstack *snum, sqstack *sop, char op)
+{
+    datatype old_op;
+
+    if (st_isempty(sop) || op == '(')
+    {
+        st_push(sop, &op);
+        return;
+    }
+
+    st_top(sop, &old_op);
+
+    if (get_pri(op) > get_pri(old_op))
+    {
+        st_push(sop, &op);
+        return;
+    }
+
+    while (get_pri(op) <= get_pri(old_op))
+    {
+        st_pop(sop, &old_op);
+        compute(snum, &old_op);
+        if (st_isempty(sop))
+            break;
+
+        st_top(sop, &old_op);
+    }
+    st_push(sop, &op);
+}
+
+
+int main()
+{
+    int      i;
+    char     str[] = "(11+3)*2-5";
+    sqstack *snum, *sop;
+    int      value = 0;
+    int      flag  = 0;
+    int      old_op;
+
+    snum = st_create();
+    if (NULL == snum)
+        exit(1);
+
+    sop = st_create();
+    if (NULL == sop)
+        exit(1);
+
+    while (str[i] != '\n')
+    {
+        if (str[i] >= '0' && str[i] <= '9')
+        {
+            value = 10 * value + (str[i] - '0');
+            flag  = 1;
+        }
+        else   // is a op
+        {
+            if (flag)
+            {
+                st_push(snum, &value);
+                flag  = 0;
+                value = 0;
+            }
+
+            if (str[i] == ')')
+            {
+                deal_bracket(snum, sop);
+            }
+            else   // ( + - * /
+            {
+                deal_op(snum, sop, str[i]);
+            }
+        }
+        i++;
+    }
+
+    if (flag)
+        st_push(snum, &value);
+
+    while (!st_isempty(sop))
+    {
+        st_pop(sop, &old_op);
+        compute(snum, &old_op);
+    }
+
+
+
+
+    st_destroy(snum);
+    st_destroy(sop);
+
+    exit(0);
+}

Chapter11/ds/line/compute/sqstack.c

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+#include <stdio.h>
+#include <stdlib.h>
+
+#include "sqstack.h"
+
+sqstack *st_create(void)
+{
+    sqstack *st;
+
+    st = malloc(sizeof(*st));
+    if (NULL == st)
+        return NULL;
+
+    st->top = -1;
+
+    return st;
+}
+
+int st_isempty(sqstack *st)
+{
+    return (-1 == st->top);
+}
+
+int st_push(sqstack *st, datatype *data)
+{
+    if (MAXSIZE - 1 == st->top)
+        return -1;
+
+    st->data[++st->top] = *data;
+
+    return 0;
+}
+
+/* 取出栈顶元素 */
+int st_pop(sqstack *st, datatype *data)
+{
+    if (st_isempty(st))
+        return -1;
+
+    *data = st->data[st->top--];
+
+    return 0;
+}
+
+
+/* 查看栈顶元素 */
+int st_top(sqstack *st, datatype *data)
+{
+    if (st_isempty(st))
+        return -1;
+
+    *data = st->data[st->top];
+
+    return 0;
+}
+
+void st_travel(sqstack *st)
+{
+    if (st_isempty(st))
+        return;
+
+    int i;
+
+    for (i = 0; i <= st->top; i++)
+        printf("%d ", st->data[i]);
+    printf("\n");
+}
+
+void st_destroy(sqstack *st)
+{
+    free(st);
+}

Chapter11/ds/line/compute/sqstack.h

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+#ifndef SQSTACK_H__
+#define SQSTACK_H__
+
+#define MAXSIZE 32
+
+typedef int datatype;
+
+typedef struct node_st
+{
+    datatype data[MAXSIZE];
+    int      top;
+} sqstack;
+
+sqstack *st_create(void);
+
+int st_isempty(sqstack *);
+
+int st_push(sqstack *, datatype *);
+
+/* 取出栈顶元素 */
+int st_pop(sqstack *, datatype *);
+
+/* 查看栈顶元素 */
+int st_top(sqstack *, datatype *);
+
+void st_travel(sqstack *);
+
+void st_destroy(sqstack *);
+
+#endif