Home > Article > Software Tutorial > How to read the two lines of character data between begin and end in a TXT document in C language
Assume the file structure is: 1E1F 0309 luan7 8 zao
2E2F 1518
begin
12 39692
12 39712
9 39724
end
begin
14 39692
8 39724
end
luan7 8 zao
qi qi guai guai
begin
312 39692
142 39712
95 39724
end
Contains multiple segments of begin, end data
#include #include
main( ) {
FILE *fin;
int a[1000],b[1000],n=0,i;
char one_line[80];
fin=fopen("abc.txt","r");
if (fin==NULL){printf("open file error\n");return 0;}
Lab1:while(1){
if ( fgets(one_line,80,fin)==NULL){
printf("Can not fund begin any more\n");goto Lab2;}
if (strncmp(one_line,"begin",5)==0)break;
}
for (i=0;i
if (strncmp(one_line,"end",3)==0)break;
sscanf(one_line,"%d %d",&a[n],&b[n]);
n ;
}
goto Lab1;
Lab2: fclose(fin);
printf("I read:\n");for (i=0;ireturn 0;
}
fgets reads each line of data and then uses strchr to find the position where semicolon; appears, and then performs the corresponding conversion!
This is an example I wrote to read a specified string. You can refer to this and modify it. The string to floating point number function atof
#include
#include
#define N 10
int readstr(const char* str,char p[][128],int plen,int savepos);
int main()
{
char str[]="2012/10/12;123456.0;456123.0";
char date[N][128]={0};
int len=readstr(str,date,N,0);
for (int i=0;i { printf("%s\n",date[i]); } return 0; } int readstr(const char* str,char p[][128],int plen,int savepos) { if(plen
{ printf ("The array is too small, please change the storage location!"); return 0; } static int len=0; char *find=strchr(str,';'); if(find==NULL) { strcpy(p[savepos],str); len ; return len; } else { strncpy(p[savepos],str,find-str); len ; readstr(find 1,p,N,len); } return len; } Use fgets to read a row, and use sscanf to read the first column of data The following assumes that the first column of data is used as a string, and is read using sscanf(buf,"%s",... format. Similarly, use %d for integers and %f for floating points.... #include #include main(){ char buf[100]; char col[100][30]; int n=0; FILE *fp = fopen("a.txt", "r"); while ( fgets(buf, 100, fp) != NULL) { if (sscanf(buf,"%s",col[n]) == 1){printf("%s\n", col[n]); n ; }; } return 0; } If you want to read the first number of each line, (only read one digit using format): int x[100]; ... while ( fgets(buf, 100, fp) != NULL) { if (sscanf(buf," ",&x[n]) == 1){ printf("%d\n",x[n]);n ;};How to read the next line of data of a specified string in C language in txt
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