从文本中获取特定字符并在C中打印相关行

由冷血动物发布于 2020-05-18 06:01:58

我在C中的I / O文件处理过程中遇到了几个问题。我有一个像这样的文本文件：

AAA    1    80
BBB    1    60
CCC    2    20
DDD    1    70
EEE    2    15
FFF    2    30
GGG    2    75
HHH    1    25
JJJ    2    35

我的目标是，如果用户输入1我需要打印：

AAA    1    80
BBB    1    60
DDD    1    70
HHH    1    25

并求和它们的值（80 + 60 + 70 + 25），并在用户输入2时应用相同的内容。

我编写这样的代码：

FILE *fPtr;
    char str[MAXCHAR];
    char* fileName = "/home/levent/Masaüstü/data.txt";
    int productType;

    fPtr = fopen(fileName, "r");

    if(fPtr == NULL){
        printf("Error! Colud not find file %s", fileName);
        return 1;
    }

    printf("Enter product type code (1 or 2): ");
    scanf("%d", &productType);

    while (fgets(str, MAXCHAR, fPtr) != NULL){
        printf("%s", str);        
    }

当您假设此代码可打印整个文本文件时。如何管理目标？

Angel 2020-05-18 06:01:59

You can use fscanf and read each component of the line since you know what they are, then in the same cycle you can sum the valid values:

这是一个可能的实现，并带有一些注释：

#include <stdio.h>
#define MAXCHAR 100

int main(void)
{
  FILE *fPtr;
  char str[MAXCHAR];
  char *fileName = "/home/levent/Masaüstü/data.txt";
  int productType;
  int fileProductType; //product type read from file
  int value;           //value read from file
  int sum = 0;
  fPtr = fopen(fileName, "r");

  if (fPtr == NULL)
  {
    printf("Error! Colud not find file %s", fileName);
    return 1;
  }

  printf("Enter product type code (1 or 2): ");
  scanf("%d", &productType);

  //scanf all file lines
  while (fscanf(fPtr, "%99s %d %d", str, &fileProductType, &value) == 3)
  {
    if (productType == fileProductType){ //if the type is correct
      printf("%s %d %d\n", str, fileProductType, value); //print line components
      sum += value; //sum values
    }    
  }
  printf("%d", sum); //print sum
}

another option would be to use sscanf to extract the components from the string read by fgets.

冷血动物

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