how to sort names in c by array - c

Question

I want to know how to sort name by array.
I have a ploblem about sorting and print it. I have no idea because I'm beginner for C programing. please advice me (sorry for my english) thank you.
code that i have
#include<stdio.h>
#include<string.h>
#include <ctype.h>
int main(){
int i = 0;
char choose[10];
struct Student{
char name[61];
char surname[61];
char sex[10];
char age[3];
char id[12];
float gpa;
}student[20];
for(i=0;i<20;i++){
scanf("%s %s %s %s %s %f",student[i].name, student[i].surname, student[i].sex,student[i].age,student[i].id,student[i].gpa);
}
for(int i =0;i<20;i++){
//sort
}
}

Answer 1

When a task is about sorting arrays, qsort is - in most cases - your friend.
All you need to do is to provide a compare function that tells whether one element is less, equal or larger than another element. Then qsort handles the rest.
Example:
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
struct Student{
char name[61];
char surname[61];
char sex[10];
char age[3];
char id[12];
float gpa;
};
void printData(struct Student* s, int n)
{
for (int i=0; i<n; ++i)
{
printf("%s %s %s %s %s %f\n",
s[i].sex, s[i].name, s[i].surname, s[i].age, s[i].id, s[i].gpa);
}
}
// Compare function for qsort
int cmp(const void *p1, const void *p2)
{
struct Student* pa = (struct Student*)p1;
struct Student* pb = (struct Student*)p2;
return strcmp(pa->name, pb->name);
}
int main(void)
{
struct Student data[3] = {
{"bbb", "bbbb", "Mr", "42", "idx", 42.0},
{"ccc", "cccc", "Ms", "42", "idy", 43.0},
{"aaa", "aaaa", "Mr", "42", "idz", 44.0}
};
printf("Before sorting:\n");
printData(data, 3);
qsort(data, 3, sizeof data[0], cmp);
printf("After sorting:\n");
printData(data, 3);
return 0;
}
Output:
Before sorting:
Mr bbb bbbb 42 idx 42.000000
Ms ccc cccc 42 idy 43.000000
Mr aaa aaaa 42 idz 44.000000
After sorting:
Mr aaa aaaa 42 idz 44.000000
Mr bbb bbbb 42 idx 42.000000
Ms ccc cccc 42 idy 43.000000

Answer 2

#include <stdio.h>
#include <string.h>
void main()
{
char name[10][8], tname[10][8], temp[8];
int i, j, n;
printf("Enter the value of n \n");
scanf("%d", &n);
printf("Enter %d names n \n", n);
for (i = 0; i < n; i++)
{
scanf("%s", name[i]);
strcpy(tname[i], name[i]);
}
for (i = 0; i < n - 1 ; i++)
{
for (j = i + 1; j < n; j++)
{
if (strcmp(name[i], name[j]) > 0)
{
strcpy(temp, name[i]);
strcpy(name[i], name[j]);
strcpy(name[j], temp);
}
}
}
printf("\n----------------------------------------\n");
printf("Input NamestSorted names\n");
printf("------------------------------------------\n");
for (i = 0; i < n; i++)
{
printf("%s\t\t%s\n", tname[i], name[i]);
}
printf("------------------------------------------\n");
}