I have received a code from a friend of mine which was giving garbage outputs and hence I tried to run it on my PC too. The same problem is happening with me and I don't know how to fix it. Here is the code to accept and display a few information of bank customers from the user and display it.
#include <stdio.h>
#include <stdlib.h>
#include <conio.h>
#include <string.h>
typedef struct Customer {
char name[20];
int date;
int month;
int year;
int amount;
int type_of_account;
} cus;
void display(int n);
void data_entry_of_customers(int n);
int main() {
int i, n, choices;
printf("\n Enter the number of customer you want to enter their data : ");
scanf("%d", &n);
do {
printf("\n Enter your choice :");
scanf("%d", &choices);
switch (choices) {
case 1:
data_entry_of_customers(n);
break;
case 2:
display(n);
break;
case 3:
exit(0);
break;
default:
{
printf("\n Invalid Choice");
}
}
i ;
} while (choices != 3);
getch();
return 0;
}
void data_entry_of_customers(int n) {
cus c[n];
int i;
for (i = 0; i < n; i ) {
printf("\n Enter the name of the customer%d : ", i 1);
scanf("%s", c[i].name);
printf("\n Enter the date when the account was opened by customer : ");
scanf("%d", &c[i].date);
printf("\n Enter the month when the account was opened by customer : ");
scanf("%d", &c[i].month);
printf("\n Enter the year when the account was opened by customer : ");
scanf("%d", &c[i].year);
printf("\n Enter the amount disposited by the customer : ");
scanf("%d", &c[i].amount);
}
}
void display(int n) {
cus c[n];
int i;
for (i = 0; i < n; i ) {
printf("\n The name of the customer%d is %s", i 1, c[i].name);
printf("\n The date-month-year when the account was opened by customer%d is %d-%d-%d", i 1, c[i].date, c[i].month, c[i].year);
printf("\n The amount when the account was opened by customer%d is %d", i 1, c[i].amount);
printf("\n");
}
}
I tried to look for errors in my code initially but it looked good to me hence I proceeded with an online compiler and now I am clueless on how should I fix the IDE's problem
CodePudding user response：
The c array is defined as a local variable in both the display and the data_entry_of_customers functions. The values entered are lost when the function returns and the contents of c in the display function are indeterminate producing undefined behavior (garbage output).
The program may seem to behave as expected if, by chance, the position and contents of the c array in both functions happens to be the same.
You should more the definition of the array to the main function and pass it to data_entry_of_customers() and display().
Here is a modified version:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
typedef struct Customer {
char name[20];
int date;
int month;
int year;
int amount;
int type_of_account;
} cus;
void display(int n, cus c[n]);
void data_entry_of_customers(int n, cus c[n]);
int main() {
int n, choices;
printf("\n Enter the number of customers : ");
if (scanf("%d", &n) != 1)
return 1;
cus cus_array[n];
for (;;) {
printf("\n Enter your choice :");
if (scanf("%d", &choices) != 1)
break;
switch (choices) {
case 1:
data_entry_of_customers(n, cus_array);
break;
case 2:
display(n, cus_array);
break;
case 3:
return 0;
default:
printf("\n Invalid Choice\n");
break;
}
}
return 0;
}
void data_entry_of_customers(int n, cus c[n]) {
for (int i = 0; i < n; i ) {
printf("\n Enter the name of the customer%d : ", i 1);
scanf("s", c[i].name);
printf("\n Enter the date when the account was opened by customer : ");
scanf("%d", &c[i].date);
printf("\n Enter the month when the account was opened by customer : ");
scanf("%d", &c[i].month);
printf("\n Enter the year when the account was opened by customer : ");
scanf("%d", &c[i].year);
printf("\n Enter the amount deposited by the customer : ");
scanf("%d", &c[i].amount);
}
}
void display(int n, cus c[n]) {
for (int i = 0; i < n; i ) {
printf("\n The name of the customer%d is %s", i 1, c[i].name);
printf("\n The date-month-year when the account was opened by customer%d is %d-%d-%d", i 1, c[i].date, c[i].month, c[i].year);
printf("\n The amount when the account was opened by customer%d is %d", i 1, c[i].amount);
printf("\n");
}
}
Note these remarks:
void display(int n, cus c[n]);defines a function that receives anintand a pointer to an array ofcusstructures. The prototype is equivalent to:void display(int n, cus c[]);andvoid display(int n, cus *c);... A possible improvement is to specify that thecusstructures are not modified by thedisplayfunction, thus change the prototype tovoid display(int n, const cus *c);the return value of
scanfshould be tested to detect and handle invalid input. Writing separate functions to read a string and an integer would help make the code more reliable and readable.
Here is an alternate approach:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
typedef struct Customer {
char name[20];
int date;
int month;
int year;
int amount;
int type_of_account;
} cus;
char *enter_string(const char *prompt, char *dest, size_t size);
int enter_int(const char *prompt, int min, int max);
void display(int n, const cus *c);
void data_entry_of_customers(int n, cus *c);
int main() {
int n = enter_int("Enter the number of customers", 1, 1000);
cus cus_array[n];
for (;;) {
switch (enter_int("Enter your choice", 1, 3)) {
case 1:
data_entry_of_customers(n, cus_array);
break;
case 2:
display(n, cus_array);
break;
case 3:
return 0;
}
}
}
char *enter_string(const char *prompt, char *dest, size_t size) {
int c;
size_t i = 0;
printf("%s: ", prompt);
fflush(stdout);
while ((c = getchar()) != EOF && c != '\n') {
if (i 1 < size) {
dest[i ] = (char)c;
}
}
printf("\n");
if (i == 0 && c == EOF) {
printf("unexpected end of file\n");
exit(1);
}
if (i < size)
dest[i] = '\0';
return dest;
}
int enter_int(const char *prompt, int min, int max) {
int c, res, value;
for (;;) {
printf("%s: ", prompt);
fflush(stdout);
res = scanf("%d", &value);
while ((c = getchar()) != EOF && c != '\n')
continue;
printf("\n");
if (res == 1) {
if (value >= min && value <= max)
return value;
printf("invalid value, must be between %d and %d\n", min, max);
} else {
if (c == EOF) {
printf("unexpected end of file\n");
exit(1);
}
printf("invalid input, enter a number between %d and %d\n", min, max);
}
}
}
void data_entry_of_customers(int n, cus *c) {
char prompt[80];
for (int i = 0; i < n; i ) {
snprintf(prompt, sizeof prompt, "Enter the name of the customer%d", i 1);
enter_string(prompt, c[i].name, sizeof(c[i].name));
c[i].date = enter_int("Enter the date when the account was opened by customer",
1, 31);
c[i].month = enter_int("Enter the month when the account was opened by customer",
1, 12);
c[i].year = enter_int("Enter the year when the account was opened by customer",
1900, 2100);
c[i].amount = enter_int("Enter the amount disposited by the customer",
0, 1000000000);
}
}
void display(int n, const cus *c) {
for (int i = 0; i < n; i ) {
printf("The name of the customer%d is %s\n", i 1, c[i].name);
printf("The date-month-year when the account was opened by customer%d is %d-%d-%d\n",
i 1, c[i].date, c[i].month, c[i].year);
printf("The amount when the account was opened by customer%d is %d\n",
i 1, c[i].amount);
printf("\n");
}
}