逐行閱讀C和標識元素

Question

我有一個文件，它的行是那種形式。

39.546147 19.849505 Name Last 

我不知道我有多少行。我想要的是逐行讀取文本，並簡單地保留這四個元素中的每一個。 （2輛花車和2個蜇-char []在這種情況下）。

到目前爲止我的代碼是這樣的：

#include <stdio.h> 
#include <stdlib.h> 

int main(int argc, char *argv[]) 
{ 
    FILE * file1; 

file1 = fopen("args.txt","r"); 
float var0; 
float var1; 
char S1 [128]; 
char S2 [128]; 
int assignments; 

if (file1 != NULL){ 
    char line [ 256 ]; 
    while (fgets (line, sizeof line, file1) != NULL) //read a line 
    { 
     //printf("%s\n",line); 
     assignments = fscanf(file1, "%f %f %s %s",&var0, &var1, &S1, &S2); 
      if(assignments < 4){ 
       fprintf(stderr, "Oops: only %d fields read\n", assignments); 
      } 
     printf("%f --- %f ---- %s ---- %s \n",var0, var1,S1,S2); 
    } 
    fclose (file1); 

} 
else { 
    perror ("args.txt"); /* why didn't the file open? */ 
} 
return 0; 
} 

，結果我得到的是，它只讀一個元素。你能幫助我嗎？ args.txt

39.546147 19.849505 george papad 

39.502277 19.923813 nick perry 

39.475508 19.934671 john derrick 

Answer 1

通過

assignments = sscanf(line, "%f %f %s %s",&var0, &var1, &S1, &S2); 

更新替換

assignments = fscanf(file1, "%f %f %s %s",&var0, &var1, &S1, &S2); 

：下面的程序在這裏工作。

#include <stdio.h> 
#include <stdlib.h> 

int main(int argc, char *argv[]) 
{ 
FILE * file1; 

float var0; 
float var1; 
char S1 [128]; 
char S2 [128]; 
char line [ 256 ]; 
int assignments; 

file1 = fopen("args.txt","r"); 

if (file1 == NULL){ 
     perror ("args.txt"); /* why didn't the file open? */ 
     return 1; 
     } 

    while (fgets (line, sizeof line, file1) != NULL) //read a line 
    { 
     //printf("%s\n",line); 
     assignments = sscanf(line, "%f %f %s %s",&var0, &var1, S1, S2); 
      if(assignments < 4){ 
       fprintf(stderr, "Oops: only %d fields read\n", assignments); 
       continue; /* <<----- */ 
      } 
     printf("%f --- %f ---- %s ---- %s \n",var0, var1,S1,S2); 
    } 
    fclose (file1); 

return 0; 
} 

OUTPUT（用於與空行輸入文件）

39.546146 --- 19.849504 ---- george ---- papad 
Oops: only -1 fields read 
39.546146 --- 19.849504 ---- george ---- papad 
39.502277 --- 19.923813 ---- nick ---- perry 
Oops: only -1 fields read 
39.502277 --- 19.923813 ---- nick ---- perry 
39.475510 --- 19.934671 ---- john ---- derrick 

這是預期的，應該有一個繼續（或等同物）在糟糕塊。

我加了繼續說明。

輸出，用於同該方案繼續：

39.546146 --- 19.849504 ---- george ---- papad 
Oops: only -1 fields read 
39.502277 --- 19.923813 ---- nick ---- perry 
Oops: only -1 fields read 
39.475510 --- 19.934671 ---- john ---- derrick 

Answer 2

您正在閱讀的線用於fgets文本，然後將其丟棄（因爲你的fscanf再次讀取）的

例子。

而不是調用fgets作爲您的while循環守衛，請考慮使用函數feof。因此，環路防護將成爲

while(!feof(file1))