Question

URGENT. Need help editing some C code. I have done most of the code it just needs the following added:

1. takes an input file name from the command line;
2. opens that file if possible;
3. declares a C struct with three variables; these will have data types that correspond to the data types read from the file (i.e. string, int, float);
4. declares an array of C structs (i.e. the same struct type declared in point c);
5. reads a record from the file and stores the values read into the appropriate struct variable at the appropriate array index (for that record);
6. continues reading each record into a struct (as in point 1e), and stores each struct containing the 3 values into the array of structs declared in point d;
7. closes the file when all records have been read.

CODE:

#include
#include
#include

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

int line_count = 0;
int index, i;

typedef struct info{
char name[100];
int age;
float wage;
} info;

info hr[10];

if (argc != 2)
printf("Invalid user_input!\n");
else {
FILE* contents = fopen (argv[1], "r");
struct info in;
  
if (contents != NULL) {
printf("File has been opened successfully.\n\n");
while (fscanf(contents, "%s %d %f\n",names[line_count], &age[line_count], &wage[line_count]) != EOF) {
printf("%s %d %f\n", names[line_count], age[line_count], wage[line_count]);
line_count++;
}
printf("\nTotal number of lines in document are: %d\n\n", line_count);
fclose(contents);
printf("Please enter a name: ");

fgets(user_input, 30, stdin);
user_input[strlen(user_input)-1] = '\0';

index = -1;
for(i = 0; i < line_count; i++){
if(strcmp(names[i], user_input) == 0){
index = i;
break;
}
}
if(index == -1)
printf("Name %s not found\n", user_input);
else{
      while(fread(&in, sizeof(struct info), 1, contents))
        printf("Name: %s, Age: %d, Wage: %.2f\n", user_input, in.age, in.wage);
}
} else {
printf("File cannot be opened!");
}
}

return 0;
}

Answer 1

The implementation of given features is shown in the below C code:

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

struct info{
char names[100];
int age;
float wage;
};

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

int line_count = 0;
int index, i;

struct info hr[10];

if (argc != 2)
printf("Invalid user_input!\n");
else {
FILE* contents = fopen (argv[1], "r");
struct info in;
  
if (contents != NULL) {
printf("File has been opened successfully.\n\n");
while (fscanf(contents, "%s %d %f\n",hr[line_count].names, &hr[line_count].age, &hr[line_count].wage) != EOF) {
printf("%s %d %f\n", hr[line_count].names, hr[line_count].age, hr[line_count].wage);
line_count++;
}
printf("\nTotal number of lines in document are: %d\n\n", line_count);
fclose(contents);
printf("Please enter a name: ");
char user_input[100];
fgets(user_input, 30, stdin);
user_input[strlen(user_input)-1] = '\0';

index = -1;
for(i = 0; i < line_count; i++){
if(strcmp(hr[i].names, user_input) == 0){
index = i;
break;
}
}
if(index == -1)
printf("Name %s not found\n", user_input);
else{
while(fread(&in, sizeof(struct info), 1, contents))
printf("Name: %s, Age: %d, Wage: %.2f\n", user_input, in.age, in.wage);
}
} else {
printf("File cannot be opened!");
}
}

return 0;
}

You have made some minor mistakes that I have corrected in above code:

• Inclusion of Header files
• Declaring structure outside the main function
• And accessing the value of structure in correct way

We access the structure variable in this way

1. hr[line_count].names //for accessing name
2. hr[line_count].age //for accessing age
3. hr[line_count].wage //for accessing wage