How to search on struct char c? - c

Question

#include<stdio.h>
#include<stdlib.h> //libraries
#include<string.h>
#define ARRAY_SIZE 4 //define the array size is 4
Declare a Person structure containing the following two data members: name and age.
struct Person
{
char name[20];
int age;
};
Define fillPersons function that takes an empty array of Persons, and fills the array.
void fillPersons(struct Person * myPs);
For function using
struct Person p[ARRAY_SIZE];
Define searchPerson function that takes an array of Persons, and the name to search for. The function will return the corresponding age if the person is found, -1 otherwise.
int searchPerson(struct Person * myPs, char * myName);
Define printPersons function that takes an array of Persons, and prints the content of the array.
void printPersons(struct Person * myPs);
Main Fuction
int main()
{
struct Person p[ARRAY_SIZE];
int a;
int isFound;
char myName[20];
Switch case for user interface
do
{
printf("1)FILL ARRAY\n");
printf("2)SEARCH BY NAME\n");
printf("3)PRINT ARRAY\n");
printf("4)EXIT\n");
printf("Search Operation:");
scanf_s("%d", &a);
switch (a)
{
case 1:fillPersons(p); break;
I write the main part of searching but i cant fill the function.
case 2:printf("\Give the name to search for:");
scanf_s("%s", &myName);
isFound = searchPerson(p, myName);
if (isFound == -1)
{
printf("%s not avaible in the array. \n", myName);
}
else
{
printf("The age of %s is %d.\n", myName, isFound);
}
break;
After this part it is okay to read names and ages but cant do it searching part.
case 3:printPersons(p); break;
case 4:printf("\nProgram exits ..."); exit(0);
}
} while (a != 4);
system("pause");
return 0;
}
It is okay this scanf part
void fillPersons(struct Person * myPs)
{
int i;
for (i = 0; i < 4; i++)//defining 4 person i<4
{
scanf_s("%20s", p[i].name,_countof(p[i].name));//if i dont do _coutof
scanf_s("%d", &p[i].age); // i get null.ptr error
} // on visiual studio
}
Printing the student names and ages
void printPersons(struct Person * myPs)
{
int i;
for (i = 0; i < 4; i++)
{
printf("%s %d", p[i].name, p[i].age);
}
}
But i dont know how to fill with inside on fuction?
int searchPerson(struct Person * myPs, char * myName)
THE OUTPUT SHOULD BE LIKE THIS

Answer 1

Seems the function you are missing is strcmp to compare two strings.
It could be like:
int searchPerson(struct Person * myPs, char * myName)
{
int i;
for (i = 0; i < ARRAY_SIZE; i++)
{
if (strcmp(myPs[i].name, myName) == 0)
{
return myPs[i].age;
}
}
return -1;
}
In general notice:
When you pass the array to a function as struct Person * myPs, you must use myPs inside the function. Further you should use the defined array size instead of hard coding a 4.
So your printPersons should be:
void printPersons(struct Person * myPs)
{
int i;
for (i = 0; i < ARRAY_SIZE; i++)
{
printf("%s %d", myPs[i].name, myPs[i].age);
}
}
Same applies to fillPersons

Answer 2

First thing, you put in your question all the functions except the one that is giving you problems: searchPerson.
Then, your error is with this instruction:
scanf_s("%s", &myName);
Accordingly that you declared myName as a char pointer, this way, you're assigning the string to the address of myName, not to the memory cells it's pointing to.
Instead, this should be:
scanf_s("%s", myName);