4-4.txt

《C/C++完美演绎》源代码

/* 范例：4-4 */
#include <stdio.h>
void main()
{
  int a=5;
  char *str = "abcd";

  /* -,+,blank => 数值type */
  printf("Flags = -,+,blank ........数值类型\n");
  printf("#%+4d#(%%+4d)\n",10);       			/* #1.1 */
  printf("#%+4d#(%%+4d)(<0)\n",-10);  			/* #1.2 */
  printf("#%-4d#(%%-4d)\n",10);       			/* #1.3 */
  printf("#%-4d#(%%-4d)(<0)\n",-10);  			/* #1.4 */
  printf("#% 4d#(%% 4d)\n",10);      		 	/* #2 */
  printf("#%+7.3g#(%%+7.3g)\n\n",10.2); 			/* #3 */

  /* - => char type */
  printf("Flags = -,+,blank ........字符(字符串)类型\n");
  printf("#%5s#(%%5s)\n",str);    			/* #4.1 靠右(默认) */
  printf("#%-5s#(%%-5s)\n",str);  			/* #4.2 靠左 */
  printf("#%3c#(%%3c)\n",'A');    			/* #5.1 靠右(默认) */
  printf("#%-3c#(%%-3c)\n\n",'A');			/* #5.2 靠左 */

  /* # => only number */
  printf("Flags = # .......数值类型\n");
  printf("#%10o#%8x#(%%10o,%%8x)\n",&a,&a);		/* #6.1 */
  printf("#%010o#%08x#(%%010o,%%08x)\n",&a,&a);	/* #6.2 */
  printf("#%#10o#%#8x#(%%#10o,%%#8x)\n\n",&a,&a);	/* #6.3 */

  printf("测试以#标识浮点数....当输入10.0时......\n");
  printf("#%7.3g#(%%7.3g)\n",10.0);    				/* #7.1 */
  printf("#%#7.0f#(%%#7.0f)\n",10.0);  				/* #7.2 */
  printf("#%#7.2e#(%%#7.2e)\n",10.0);  				/* #7.3 */
  printf("#%#7.3g#(%%#7.3g)\n",10.0);  				/* #7.4 */

  getchar();
  /* 混用Flags(-,+,blank,#) */
  printf("Flags = -,+,blank,#混用 ...(输入10.2)......\n");
  printf("#%+#7.4g#(%%+#7.4g)\n",10.2);			 	/* #8.1 */
  printf("#%+ 7.4g#(%%+ 7.4g)\n",10.2); 				/* #8.2 */
  printf("#%# -+7.4g#(%%# -+7.4g)\n",10.2);			/* #8.3 */
  printf("#%-+# 7.4g#(%%-+# 7.4g)\n",10.2);			/* #8.4 */

  getchar();
}

程序执行结果：
Flags = -,+,blank ........数值类型
# +10#(%+4d)
# -10#(%+4d)(<0)
#10  #(%-4d)
#-10 #(%-4d)(<0)
#  10#(% 4d)
#  +10.2#(%+7.3g)

Flags = -,+,blank ........字符(字符串)类型
# abcd#(%5s)
#abcd #(%-5s)
#  A#(%3c)
#A  #(%-3c)

Flags = # .......数值类型
#  31177000#  64fe00#(%10o,%8x)
#0031177000#0064fe00#(%010o,%08x)
# 031177000#0x64fe00#(%#10o,%#8x)

测试以#标识浮点数....当输入10.0时......
#     10#(%7.3g)
#    10.#(%#7.0f)
#1.00e+01#(%#7.2e)
#   10.0#(%#7.3g)
Flags = -,+,blank,#混用 ...(输入10.2)......
# +10.20#(%+#7.4g)
#  +10.2#(%+ 7.4g)
#+10.20 #(%# -+7.4g)
#+10.20 #(%-+# 7.4g)