46.数字到字符串的转换

1     char buffer[128];
2     double value = 12.2345678;
3     _gcvt(value, 5, buffer);//5有效数字
4     printf("%s", buffer);

 1     unsigned int num = 32;
 2     char str[32] = { 0 };
 3     //以2进制方式转换
 4     _ultoa(num, str, 2);
 5     printf("%s\n", str);
 6 
 7     //以8进制方式转换
 8     _ultoa(num, str, 8);
 9     printf("%s\n", str);
10 
11     //以10进制方式转换
12     _ultoa(num, str, 10);
13     printf("%s\n", str);
14     //以16进制方式转换
15     _ultoa(num, str, 16);
16     printf("%s\n", str);

 1     int num = -32;
 2     char str[32] = { 0 };
 3     _ltoa(num, str, 2);
 4     printf("%s\n", str);
 5 
 6     _ltoa(num, str, 8);
 7     printf("%s\n", str);
 8     _ltoa(num, str, 10);
 9     printf("%s\n", str);
10     _ltoa(num, str, 16);
11     printf("%s\n", str);

 1         double data = 12345.4567;
 2     
 3     int decimal;//整数的位数
 4     int sign;//1代表负，0代表证
 5     int precision = 9;//数字的宽度，强行指定
 6     char *buffer;//指针
 7 
 8     //把double类型转化为char*
 9     buffer = _ecvt(data, precision, &decimal, &sign);//自动分配内存
10     printf("buffer=%s\n", buffer);
11     printf("sign=%d\n", sign);
12     printf("decimal=%d\n", decimal);
13     printf("precision =%d\n", precision);    

 1     double data = 12345.4567;
 2 
 3     int decimal;//整数的位数
 4     int sign;//1代表负，0代表证
 5     int precision = 4;//小数点后的精度
 6     char *buffer;//指针
 7 
 8     buffer=_fcvt(data, precision, &decimal, &sign);
 9     printf("buffer=%s\n", buffer);
10     printf("sign=%d\n", sign);
11     printf("decimal=%d\n", decimal);
12     printf("precision =%d\n", precision);
13