课后题答案
<p>一、选择题</p>
<p>1．D 2．C 3．D 4．B 5．B</p>
<p>二、填空题</p>
<p>1．27\n</p>
<p>2．12</p>
<p>3．scanf("%d",&a);</p>
<p>三、编程题</p>
<p>1．参考代码如下：</p>
<pre><code class="language-c">#include &lt;stdio.h&gt;
int main()
{
int x;
float y,s;
printf(&quot;请输入商品的单价&quot;);
scanf(&quot;%f&quot;,&amp;y);
printf(&quot;请输入购买商品的个数&quot;);
scanf(&quot;%d&quot;,&amp;x);
s=x*y;
printf(&quot;商品总价为： %f\n&quot;,s);
return 0;
}</code></pre>
<p>2．参考代码如下：</p>
<pre><code class="language-c">#include &lt;stdio.h&gt;
int main()
{
int a,b;
printf(&quot;请输入a和b的值&quot;);
scanf(&quot;a=%d,b=%d&quot;,&amp;a,&amp;b);
a=a+b;
b=a-b;
a=a-b;
printf(&quot;a=%d,b=%d\n&quot;,a,b);
return 0;
}</code></pre>
<p>3．参考代码如下：</p>
<pre><code class="language-c">#include&lt;stdio.h&gt;
int main()
{
printf(&quot; ****\n&quot;);
printf(&quot; *\n&quot;);
printf(&quot; * \n&quot;);
printf(&quot; ****\n&quot;);
return 0;
}</code></pre>
<p>4．参考代码如下：</p>
<pre><code class="language-c">#include&lt;stdio.h&gt;
int main()
{
int a=5;
float b=1.332;
char c='A';
printf(&quot;a=%4d b=%.3f\n&quot;,a,b);
printf(&quot;a+b=%.1f\n&quot;,a+b);
printf(&quot;c=\'%c\' or %d\n&quot;,c,c);
return 0;
}</code></pre>