我正在从文件中读取时间，然后尝试将读取时间转换为秒。是否有更简单的方法来转换时间戳？我的方法似乎效率低下。在写入文件时，您认为什么是最好的方法？
示例文件
My test file
00:19.1 123456
00:35.4 testing whitespace end
Desired Output
1: My test file
2: 00:19.1
3: 00:35.4
代码：
#include <stdio.h>
#define MAXC 1024 // define constants, don't use magic number in code
#define MAXN 40
int main (int argc, char **argv) {
char buf[MAXC] = ""; // buffer to hold each line -- size as reqd
char filename[MAXN];
int line = 1;
int replace_line;
FILE *fp, *fp2;
printf("Please enter a file name: ");
scanf("%s",&filename);
fp = fopen(filename,"r+");
if (!fp) // validate file open for reading
{
fprintf (stderr, "error: file open failed '%s'.\n", argv[1]);
return 1;
}
//printf("Enter a increment of time: ");
//scanf("%d", &increment);
while (fgets (buf, sizeof buf, fp)) // read each line in file
{
char et[MAXC] = ""; // buffer for holding time
char etR[MAXC] = "";
char time[7] = "";
int filler = 0;
if (line == 1) // if 1st line, just print
{
printf ("%d : %s", line, buf); // note: \n included by fgets
//fprintf(fp2,"%s",buf);
} // end of if first line
else
{
if (sscanf (buf, "%s", et) != 1) // parse up to first whitespace
{
fprintf (stderr, "error: invalid conversion, line %d\n", line);
return 1;
}
printf ("%d : %s\n", line, et); //output elapsed time only
while(filler < 7)
{
time[filler] = et[filler];
filler++;
}
time[1] = time[1] - '0'; //Leading Minute (error if over 6)
time[2] = time[2] - '0'; //Minute
time[4] = time[4] - '0'; //Leading Second (Add to minute if over 6)
time[5] = time[5] - '0'; //Second (Add to LS if over 9)
time[7] = time[7] - '0'; //fraction of a second (Add to S if over 9)
float timeInSeconds;
char minuteHolder[2];
sprintf(minuteHolder,"%d%d",time[1],time[2]);
int minute;
minute = (minuteHolder[0]*10) + minuteHolder[1];
printf("\n%d\n",minute);
//getting 539 , minutes on every line???
} //end of else
line++; // increment line count
} // end of while parsing file
rewind(fp);
if (fp != stdin) // close file if not stdin
{
fclose (fp);
}
return 0;
}
答案 0 :(得分：0)
转换源字符串：“00：19.1 123456” 到dest字符串：“1. 00：19.1”
现在，我们有了代码：
#include <stdio.h>
#define MAXC 1024 // define constants, don't use magic number in code
#define MAXN 40
int main(int argc, char **argv) {
char buf[MAXC] = ""; // buffer to hold each line -- size as reqd
char filename[MAXN];
int line = 1;
int replace_line;
//FILE *fp = argc > 1 ? fopen (argv[1], "r") : stdin;
//FILE *fp = fopen("test.txt","r");
FILE *fp, *fp2;
printf("Please enter a file name: ");
scanf("%s", &filename);
fp = fopen(filename, "r+");
//fp2 = fopen("datadump.txt","w");
if (!fp) // validate file open for reading
{
fprintf(stderr, "error: file open failed '%s'.\n", argv[1]);
return 1;
}
//printf("Enter a increment of time: ");
//scanf("%d", &increment);
while (fgets(buf, sizeof buf, fp)) // read each line in file
{
char et[MAXC] = ""; // buffer for holding time
char etR[MAXC] = "";
char time[7] = "";
int filler = 0;
if (line == 1) // if 1st line, just print
{
printf("%d : %s", line, buf); // note: \n included by fgets
//fprintf(fp2,"%s",buf);
} // end of if first line
else
{
char *pblack = strchr(buf, ' '); // get chr ' ' pos
pblack[0] = 0; // set ' ' to '\0', get the new string
printf("%d : %s\n", line, buf);
} //end of else
line++; // increment line count
} // end of while parsing file
rewind(fp);
//fp2 = fopen("replica.c","w");
//replacement code
/*
flcose(fp);
fclose(fp2);
remove(filename(;
rename("replica.c",filename);
//if you to show them new file fflush stdin and repeat while
//fp = fopen(filename, "r");
//while loop
*/
if (fp != stdin) // close file if not stdin
{
fclose(fp);
//fclose (fp2);
}
return 0;
}
答案 1 :(得分：0)
如果时间格式为增量后的相同，则可以将时间字段替换为fseek而不重写整个文件。
显示了一个总体示例。请更改详细信息
试试这个
#include <stdio.h>
#include <string.h>
#include <ctype.h>
#define MAXC 1024 //input buffer size
#define MAXLINE 1024 //max number of line
int main (int argc, char **argv) {
char filename[FILENAME_MAX+1+1];//+1: newline, +1: NUL
char buf[MAXC] = "";
char time_field[7+1];//mm:ss.s, +1: NUL
unsigned char ch;
long pos[MAXLINE];//save file positions
int line = 0; //start with 0 in program
int replace_line; //input replace line number
int increment; //input incremant second.
FILE *fp;
printf("Please enter a file name: ");
fgets(filename, sizeof filename, stdin);
filename[strcspn(filename, "\n")] = 0;//chomp newline
fp = fopen(filename, "r+");
if (!fp){
fprintf (stderr, "error: file open failed '%s'.\n", filename);
return 1;
}
//display file & store file position each line
pos[line] = ftell(fp);
while (fgets (buf, sizeof buf, fp)){
if(++line == MAXLINE){
fprintf (stderr, "error: file too long.\n");//Need change the program. expand array or use malloc and realloc
return 2;
}
pos[line] = ftell(fp);
if (!isdigit(ch = *buf)){//If it does not start with a numerical value Output as it is
printf("%d : %s", line, buf); //note: \n included by fgets
} else {
if(sscanf(buf, "%7s%c", time_field, &ch)==2 && isspace(ch)){
printf ("%d : %s\n", line, time_field);
} else {
fprintf (stderr, "error: invalid time format '%s'", buf);
return 3;
}
}
}
printf("Enter a number of edit line: ");
scanf("%d", &replace_line);
printf("Enter a increment of time: ");
scanf("%d", &increment);//sec
if(fseek(fp, pos[replace_line-1], SEEK_SET)==0){//-1: 0 start in program, 1 start in input
int m, s, ds, seconds;
fscanf(fp, "%s", time_field);
if(sscanf(time_field, "%d:%d.%d", &m, &s, &ds)!=3){
fprintf (stderr, "error: invalid time format '%s' at %d line.\n", time_field, replace_line);
return 3;
}
seconds = m * 60 + s + increment;
m = seconds / 60;
s = seconds % 60;
if(m > 99 || seconds < 0){
fprintf (stderr, "error: Can't change time format.\n");//It is necessary to rewrite the whole file.
return 4;
}
fseek(fp, pos[replace_line-1], SEEK_SET);
fprintf(fp, "%02d:%02d", m, s);fflush(fp);
} else {
fprintf (stderr, "error: file seek failed to '%d' line.\n", replace_line);
return 5;
}
fclose(fp);
return 0;
}