從文件中提取後無法將提取的數字轉換爲int

Question

我是C新手，現在我試圖從文件中提取一些數字到int，但問題是雖然我可以從文件中提取它們並將它們傳遞到一個字符數組，我不能將它們轉換爲INT，我不知道爲什麼，所以這裏是代碼：

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

char *sacardigito(char *vecchar) 
{ 
    char sodigitos[100]={},*ppsodigitos=&sodigitos,*guardarprimeiro=&sodigitos[0]; 
    do 
    { 
     if(isdigit(*vecchar)) //if the character inside current address is a digit 
     { 
      *ppsodigitos=*vecchar; //places the digit inside the char pointer (array sodigitos) 
      ppsodigitos++; //increments the pointer 
     } 
     vecchar++; //increment the pointer address (array vechar) 

    }while(*vecchar!='\0'); 
    printf("\nChar array in function is: %s ",guardarprimeiro); //prints the first position of the array just to make sure only numbers remain 
    return guardarprimeiro; 
} 

int main() 
{ 
    FILE *fp; 
    long sonumero; 
    int i; 
    char vecnumeros[100]={},*retorno; 
    fp=fopen("numbers.txt","r"); //open the numbers.txt file 
    fgets(vecnumeros,100,(FILE *)fp); //this line passes everything inside to file to a char array 
    printf("%s",vecnumeros); //print the char array in order to verify everything is ok 
    fclose(fp); //closes the file 
    retorno=sacardigito(vecnumeros); //sends to function to retrieve the digits 
    printf("\nChar array in main is: %s",retorno); //prints the retuned array 
    sscanf(retorno,"%ld",&sonumero); //Convert teh array to digits, I used this function from this user --> http://stackoverflow.com/questions/10204471/convert-char-array-to-a-int-number-in-c 
    printf("\nThe numbers in the file are the following: %ld",sonumero); //Now it gives me the error, I don't know why 
    return 0; 
} 

令我困惑的是，sscanf的不轉換數字成很長，但在這個其他代碼中，它確實（這是我僅僅嘗試從char提取數字，然後將這些數字從char轉換爲字符串的函數）：

char *validacao(char *numeros) 
{ 
    char digitos[100]={},*digitospp=&digitos,*inicio=&digitos; 
    do 
    { 
     if(isdigit(*numeros)) 
     { 
      *digitospp=*numeros; 
      digitospp++; 
     } 
     numeros++; 

    }while(*numeros!='\0'); 
    return inicio; 


} 
int main() 
{ 
    char numeros[100],*retorno; 
    long numeroemint; 
    setvbuf(stdout, NULL, _IONBF, 0); // Necessario no eclipse 
    printf("Introduza um numero --> "); 
    fgets(numeros,20,stdin); 
    retorno=validacao(numeros); 
    printf("\nO vector de chars e %s",retorno); 
    sscanf(retorno,"%ld",&numeroemint); //esta linha transforma o vector de carcacteres numa variável tipo int 
    printf("\nO numero %s so com os digitos e --> %ld",numeros,numeroemint); 
    return 0; 
} 

我錯過了什麼？

親切的問候。

編輯：

所以我改變了代碼爲R薩胡提議和它的作品，但我有一個問題。另一個用戶說了一些關於未定義的行爲和自動變量和指針......有人可以澄清這一點嗎？那麼，是不是指針只是一個內存地址，我不能從函數返回一個內存地址以便以後使用？

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

long sacardigito(char *vecchar) 
{ 
    long numeroemint; 
    char sodigitos[100]={},*ppsodigitos=&sodigitos[0],*guardarprimeiro=&sodigitos[0]; 
    do 
    { 
     if(isdigit(*vecchar)) //if the character inside current address is a digit 
     { 
      *ppsodigitos=*vecchar; //places the digit inside the char pointer (array sodigitos) 
      ppsodigitos++; //increments the pointer 
     } 
     vecchar++; //increment the pointer address (array vechar) 

    }while(*vecchar!='\0'); 
    printf("\nChar array in function is: %s ",guardarprimeiro); //prints the first position of the array just to make sure only numbers remain 
    sscanf(guardarprimeiro, "%ld", &numeroemint); 
    printf("\nChar array in function after sscanf is: %ld ",numeroemint); 
    return numeroemint; 
} 

int main() 
{ 
    FILE *fp; 
    long retorno; 
    char vecnumeros[100]={}; 
    fp=fopen("numbers.txt","r"); //open the numeros.txt file 
    fgets(vecnumeros,100,(FILE *)fp); //this line passes everything inside to file to a char array 
    printf("%s",vecnumeros); //print the char array in order to verify everything is ok 
    fclose(fp); //closes the file 
    retorno=sacardigito(vecnumeros); //sends to function to retrieve the digits 
    printf("\nChar array in main is: %ld",retorno); //prints the retuned array 
    printf("\nThe numebrs in the file are the following: %ld",retorno); //Now it gives me the error 
    return 0; 
} 

最好的問候。

Answer 1

您已經從@WhozCraig留下的評論中瞭解問題。

我的建議來解決問題：「我是什麼失蹤」

變化sacardigito到long

long sacardigito(char *vecchar) 
{ 
    long numeroemint; 
    char sodigitos[100]={},*ppsodigitos=&sodigitos,*guardarprimeiro=&sodigitos[0]; 
    do 
    { 
     if(isdigit(*vecchar)) //if the character inside current address is a digit 
     { 
      *ppsodigitos=*vecchar; //places the digit inside the char pointer (array sodigitos) 
      ppsodigitos++; //increments the pointer 
     } 
     vecchar++; //increment the pointer address (array vechar) 

    }while(*vecchar!='\0'); 
    printf("\nChar array in function is: %s ",guardarprimeiro); //prints the first position of the array just to make sure only numbers remain 
    sscanf(guardarprimeiro, "%ld", &numeroemint); 
    return numeroemint; 
} 

Answer 2

你有兩個問題。首先你要返回一個指向只存在於函數生命週期中的數組的指針，導致未定義的行爲。其次，你不是用空字符來終止字符串。