How to put a ";" at the end of the string, program in c

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How to put a ";" at the end of the string, program in c

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#1 by (1 votes)
#2 by (0 votes)
#3 by (-1 votes)

0

I would like to know what to do for the ";" no print appears after of the string and not before . I'm new to programming and would like to appeal to your help.

Thank you

Input

Linha1
Linha2
Linha3
Linha4

Expected output

Produtos:
- Linha3;
- Linha4;
- Linha2;
- Linha1;

Output Obtained

Produtos:
- Linha1
;- Linha2
;- Linha3
;- Linha4
;

Code

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

typedef struct linha {
  char *produtos;
  struct linha *prev;
} linha;

FILE *file;   
int main() {

  linha *tail = NULL;
  file = fopen("text.txt","r");
  char linha1[255];

  while (fgets(linha1,255,file)!=NULL) {
    linha *l1 =(linha*) malloc(sizeof(linha));
    l1->produtos =(char*) malloc(strlen(linha1)+1);
    strcpy(l1->produtos,linha1);
    l1->prev = tail;
    tail = l1;
  }

  linha *current;
  current = tail;
    printf("Produtos:\n");
  while (current != NULL) {
    printf("- %s;",current->produtos);
    current = current->prev;
  }
  return 0;

}

c++ string

asked by anonymous 13.01.2018 / 18:09

3 answers

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score 1 · Answer 1

Edited, because if the file being read did not end with a line break ( '\n' ), the last character would be deleted. Placed a test to verify that the last character of the read line is '\n' before replacing.

As user72726 explained in his response, the fgets function includes the line feed when reading from file ( '\n' ). At first I thought about inserting the semicolon when reading the file, but this limits some other treatment you might want to do.

I suggest taking this line feed when reading from the file

while (fgets(linha1,255,file)!=NULL) {
  linha *l1 =(linha*) malloc(sizeof(linha));
  if (linha1[strlen(linha1) - 1] == '\n') // testa se o último caractere é \n
    linha1[strlen(linha1) - 1] = 'while (current != NULL) {
  printf("- %s;\n",current->produtos);
  current = current->prev;
}
'; // troca o \n pelo char null
  l1->produtos =(char*) malloc(strlen(linha1)+1);
  strcpy(l1->produtos,linha1);
  l1->prev = tail;
  tail = l1;
}

and then add the semicolon and line feed when displaying on the screen

while (fgets(linha1,255,file)!=NULL) {
  linha *l1 =(linha*) malloc(sizeof(linha));
  if (linha1[strlen(linha1) - 1] == '\n') // testa se o último caractere é \n
    linha1[strlen(linha1) - 1] = 'while (current != NULL) {
  printf("- %s;\n",current->produtos);
  current = current->prev;
}
'; // troca o \n pelo char null
  l1->produtos =(char*) malloc(strlen(linha1)+1);
  strcpy(l1->produtos,linha1);
  l1->prev = tail;
  tail = l1;
}

It works because functions that handle strings stop when they find a null character - see ref. of the strcpy of the link below, at the end of the first sentence "including the terminating null character (and stopping at that point)".

Note that if you do sizeof(linha1) will be different from strlen(linha1) , normal, if I'm not mistaken, it's the difference being 1 but here it will be 2 because linha1 is a pointer that in the end has two null characters instead of 1, which strlen does not count.

The above paragraph is incorrect because sizeof(linha1) in the case of this program will always be 255, since it is the size allotted in the declaration.

One important thing, though out of the question, is releasing all the memory you use. So, if it were me, for each malloc I'd put a memfree in the program even though the program would close right after.

References (other functions appear in the menu on the left): link link

score 0 · Answer 2

The fgets function returns all the characters of the line, including the end-of-line character itself - \n (of course, it is the last character of the returned string). And that's why the printout is not being done the way you want it to be.

So you could choose to replace the last character of the string with a space.

Ex:

linha1[strlen(linha1) -1 ] = ' ';
strcpy(l1->produtos,linha1);

score -1 · Answer 3

The code entered in the question is not in C ++ style.

I rewrote using the C ++ libraries. Compiled with:

g ++ -std = c ++ 11 stackoverflow.cpp -o stackoverflow

#include <iostream>
#include <fstream>

using namespace std;

int main() {

    ifstream entrada("entrada.txt");
    string linha;

    while (getline(entrada, linha)) {
        cout << " - " << linha << ";" << endl;
    }

    return 0;
}