C 中的一个简单文件处理代码卡在 do/while 循环
A simple file handling code at C stuck at do/while loop
int main(void) {
int status = EXIT_SUCCESS;
FILE *in;
struct sigrecord {
int signum;
char signame[10];
char sigdesc[100];
} sigrec;
if ((in = fopen("signals.txt", "r")) == NULL) {
fputs("Cannot open signals.txt file\n", stderr);
return EXIT_FAILURE;
}
do {
int n = fscanf(in, "%d%9s%*[ \t]%99[^\n]", &sigrec.signum,
sigrec.signame, sigrec.sigdesc);
if (n == 3) {
printf("Signal\n number = %d\n name = %s\n description = %s\n\n",
sigrec.signum, sigrec.signame, sigrec.sigdesc);
} else if (n != EOF) {
fputs("Failed to match signum, signame or sigdesc\n", stderr);
status = EXIT_FAILURE;
break;
}
} while (1);
if (fclose(in) == EOF) {
fputs("Failed to close file\n", stderr);
status = EXIT_FAILURE;
}
return status;
}
输出很好,但是 while(1) 循环没有结束 do{} 循环,我的程序在完成它的目的后卡住了,完美地打印输出。感谢您的帮助。
如果 scanf
尽管有原因但没有成功,您需要 break
。
}
else {
if (n != EOF) {
fputs("Failed to match signum, signame or sigdesc\n", stderr);
status = EXIT_FAILURE;
}
break;
}
int main(void) {
int status = EXIT_SUCCESS;
FILE *in;
struct sigrecord {
int signum;
char signame[10];
char sigdesc[100];
} sigrec;
if ((in = fopen("signals.txt", "r")) == NULL) {
fputs("Cannot open signals.txt file\n", stderr);
return EXIT_FAILURE;
}
do {
int n = fscanf(in, "%d%9s%*[ \t]%99[^\n]", &sigrec.signum,
sigrec.signame, sigrec.sigdesc);
if (n == 3) {
printf("Signal\n number = %d\n name = %s\n description = %s\n\n",
sigrec.signum, sigrec.signame, sigrec.sigdesc);
} else if (n != EOF) {
fputs("Failed to match signum, signame or sigdesc\n", stderr);
status = EXIT_FAILURE;
break;
}
} while (1);
if (fclose(in) == EOF) {
fputs("Failed to close file\n", stderr);
status = EXIT_FAILURE;
}
return status;
}
输出很好,但是 while(1) 循环没有结束 do{} 循环,我的程序在完成它的目的后卡住了,完美地打印输出。感谢您的帮助。
如果 scanf
尽管有原因但没有成功,您需要 break
。
}
else {
if (n != EOF) {
fputs("Failed to match signum, signame or sigdesc\n", stderr);
status = EXIT_FAILURE;
}
break;
}