Question

Part1. Write a C program contains the following declarations: char customer_name[N_CUSTOMERS][MAX_NAME_LENGTH]; int customer_number[N_CUSTOMERS] A program uses a text file that contains the following data on each line: The customer number is an int, and the first and last names are alphabetic strings that contain no whitespace. The last and first names themselves are however separated by whitespace. Write a C function with the following prototype: void read_customer (char name[][MAX_NAME_LENGTH], int number[], int position, FILE *cust_file) Your function should read a single customer number and the last and first names from the file. Read the information using fscanf(). Store the information in the specified position in the arrays. The name should be stored in the array in the form <first>, with a space separating the two names. For example, if the file contains 1234 Smith Suzie store the string ”Suzie Smith” in the name array. (Hint: use strcat().) Do not worry about buffer overflow in this problem: assume that 0 ≤ position < N CUSTOMERS, and that any strings you manipulate have a length less than MAX NAME LENGTH. Part2. Redo the program, except assume the customer name array has been declared as char *customer_name[N_CUSTOMERS]; so the function prototype will be void read_customer (char *name[], int number[], int position, FILE *cust_file) Your function will need to dynamically allocate memory for the new string, and store a pointer to that memory in the appropriate place in the array. Make sure that the new string is no longer than it needs to be to contain the required characters.

Answer 1

// 1st

void read_customer(char name[][MAX_NAME_LENGTH], int number[], int position, FILE *cust_file) {
        
        char fName[MAX_NAME_LENGTH];
        char lName[MAX_NAME_LENGTH];
        
        fscanf(cust_file, "%d %s %s", &number[position], lName, fname);
        
        name[position][0] = '\0';
        strcat(name[position], fName);
        strcat(name[position], " ");
        strcat(name[position], lName);
}


// 2nd
void read_customer(char *name[], int number[], int position, FILE *cust_file) {
        
        char fName[MAX_NAME_LENGTH];
        char lName[MAX_NAME_LENGTH];
        
        fscanf(cust_file, "%d %s %s", &number[position], lName, fname);
        
                // taking 2 extra character, one for space, one for last null char
        name[position] = malloc(sizeof(char) * (strlen(fName) + 2 + strlen(lName)));
        strcat(name[position], fName);
        strcat(name[position], " ");
        strcat(name[position], lName);
}