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分享fwrite和fread问题
我想写入和读取几个参数到一个文件里，连续输出中一个结果是
[walk] Current position is (7,3,0.857969)Next Goal is (9,6) wx is (1,1,0.857969)
我想让写入的参数是7和3，真不知道怎么弄成wx is (7,3)
while(wb_robot_step(TIME_STEP) != -1) {
odometry_track_step(&ot);
int x = wtoc_x(ot.result.x);
int y = wtoc_y(ot.result.y);
float theta=ot.result.theta;
printf("Current position is (%d,%d,%f)",x,y,theta);
run();
FILE *com = NULL;
size_t lenx = 0;
//size_t leny = 0;
com =fopen("C:/Users/WYP/Desktop/midterm/controllers/communication","w+");
if (com== NULL) {
printf("Error in opening a file..");
}
lenx = fwrite(&x, sizeof(x),1, com);
//leny = fwrite(&y, sizeof(y), 1, com);
fclose(com);
printf(" wx is (%d,%d,%f)\n",lenx);
}
[walk] Current position is (7,3,0.857969)Next Goal is (9,6) wx is (1,1,0.857969)
我想让写入的参数是7和3，真不知道怎么弄成wx is (7,3)
while(wb_robot_step(TIME_STEP) != -1) {
odometry_track_step(&ot);
int x = wtoc_x(ot.result.x);
int y = wtoc_y(ot.result.y);
float theta=ot.result.theta;
printf("Current position is (%d,%d,%f)",x,y,theta);
run();
FILE *com = NULL;
size_t lenx = 0;
//size_t leny = 0;
com =fopen("C:/Users/WYP/Desktop/midterm/controllers/communication","w+");
if (com== NULL) {
printf("Error in opening a file..");
}
lenx = fwrite(&x, sizeof(x),1, com);
//leny = fwrite(&y, sizeof(y), 1, com);
fclose(com);
printf(" wx is (%d,%d,%f)\n",lenx);
}
...全文
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IVERS0N 2012-03-13
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fread和fwrite 应该用二进制方式打开文本
赵4老师 2012-03-13
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不要把
fopen("...","...");fscanf,fprintf,fclose //读时把\r\n替换成\n，写时把\n替换成\r\n;读到\x1a就设置EOF;读写的内容当字符看待
和
fopen("...","...b");fread,fwrite,fclose //不作以上替换，遇到\x1a仍继续读;读写的内容当字节看待
弄混了
fopen("...","...");fscanf,fprintf,fclose //读时把\r\n替换成\n，写时把\n替换成\r\n;读到\x1a就设置EOF;读写的内容当字符看待
和
fopen("...","...b");fread,fwrite,fclose //不作以上替换，遇到\x1a仍继续读;读写的内容当字节看待
弄混了
Franklin_007 2012-03-13
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printf(" wx is (%d,%d,%f)\n",lenx);
你这怎么只有lenx一个参数，应该有三个参数吧！这个编译器不报错误，但是肯定影响输出结果。
以后细心一些
你这怎么只有lenx一个参数，应该有三个参数吧！这个编译器不报错误，但是肯定影响输出结果。
以后细心一些
lida2003 2012-03-13
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size_t fread(void *ptr, size_t size, size_t nmemb, FILE *stream);
size_t fwrite(const void *ptr, size_t size, size_t nmemb,
FILE *stream);
DESCRIPTION
The function fread() reads nmemb elements of data, each size bytes long, from the stream pointed to by stream, storing them at the location given by ptr.
The function fwrite() writes nmemb elements of data, each size bytes long, to the stream pointed to by stream, obtaining them from the location given by ptr.
size_t fwrite(const void *ptr, size_t size, size_t nmemb,
FILE *stream);
DESCRIPTION
The function fread() reads nmemb elements of data, each size bytes long, from the stream pointed to by stream, storing them at the location given by ptr.
The function fwrite() writes nmemb elements of data, each size bytes long, to the stream pointed to by stream, obtaining them from the location given by ptr.
