strtod 转化异常

[dingzs3]

读取两行 double 数字：

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0 0 0 0 0.02 0.12 0.12 0.1 0.18 0.2 0.24 0.32 0.26 0.18 0.14 0.04 0.04 0.02 0.02 0 0 0 0 0 0 0 0 0 0 0 0 0 0

代码：

ptr=strtok(line," ");

if(ptr == NULL)

continue;

while(ptr != NULL) {

num = strtod(ptr,NULL);

kd_ljj.x[row][col]=num;

printf("row=%d col=%d num=%lf\n",row,col,num);

row++;

ptr=strtok(NULL," ");

}

读取完成后，为啥用 gdb 看到的是这样的：

(gdb) p kd_ljj.x

$1 = {{0, 0} <repeats 11 times>, {0, 0.02}, {0, 0.12}, {0, 0.12}, {0,

0.10000000000000001}, {0, 0.17999999999999999}, {0, 0.20000000000000001}, {0,

0.23999999999999999}, {0, 0.32000000000000001}, {0, 0.26000000000000001}, {0, 0.17999999999999999}, {0,

0.14000000000000001}, {0, 0.040000000000000001}, {0, 0.040000000000000001}, {0, 0.02},
{0, 0.02}, {0, 
0} <repeats 14 times>}

为什么中间的数字会出现偏差，而 printf 打印的又是正常的，这个是代码的问题还是什么原因

[ejq]

浮点数误差了解一下

IEEE 754 了解一下

https://0.30000000000000004.com

[dingzs3]

多谢啊