a program that uses an ID number or name as a search key to search for results in a binary search

$./a.out
Number of Data: 3
a[0]
  ID: 1
  Name: suzuki
a[1]
  ID: 2
  Name: kato
a[2]
  ID: 3
  Name: sano
1) ID, 2) Name: 2

Element ID Name
a[0]—2 kato           
a[1]—3sano           
a[2]—1 suzuki         
Search key (name): sano
Search key (name) sano, ID 3 found in a[1]

$./a.out
Number of Data: 3
a[0]
  ID: 2
  Name: kato
a[1]
  ID: 1
  Name: sano
a[2]
  ID: 4
  Name: suzuki
1) ID, 2) Name: 2

Element ID Name
a[0]—2 kato           
a[1]—1 sano           
a[2]—4 suzuki         
Search key (name): suzuki
US>Search key (name) UU not found

#include<stdio.h>
# include <string.h>
#define MAX_SIZE100

US>structure student {
    intid;
    char name [20];
};
typeedef structure student student;

/* Replace Student type values indicated by two pointer arguments */
void swap_student(structure student*a, structure student*b)
{
    structure student t=*a;
    *a=*b;
    *b=t;
}

/* Each element of the Student array a[ ] of length size is:
   Sort by id (ascending) */
void ssort_id (Student a[], intn)
{
    inti,j;
    for(i=n-1;i>=1;i--){
     for(j=0;j<i;j++){
        if(a[j].id>a[j+1].id){
             swap_student(&a[j], &a[j+1]);
        }
      }
    }
}

/* Each element of the Student array a[ ] of length size is:
   Sort by name (ascending) */
void ssort_name (Student a[], int size)
{
    inti,j;
    for(i=0;i<size;i++){
     for(j=size-1;j>i;j--){
      if(strcmp(a[j-1].name, a[j].name)>0){
       swap_student(&a[j-1], &a[j]);
      }
    }
  } 
}

/* Decide whether member id of array a[] has search key (ID) x by binary search*/
int bsearch_id (Student a[], intp, intq, intx)
{
    int = (p+q)/2;
    if(p>q){
      return-1;
    }
    if(a[t].id==x){
      return;
    }
    if(a[t].id>x){
      q = t-1;
    } else{
      p = q+1;
    }
    return bsearch_id(a,p,q,x);
}

/* Determine if member name of array a[] has search key (name) x by binary search */
int bsearch_name (Student a[], intp, intq, char x[])
{
    int = (p+q)/2;
    if(p>q){
      return-1;
    }
    if(!strcmp(a[t].name,x)){
      return;
    }
    if(strcmp(a[t].name,x)>0){
      q = t-1;
    } else{
      p = q+1;
    }
    return bsearch_name(a,p,q,x);
}

/* Store user input in each element of array a[] of length size */
void get_students (Student a[], int size)
{
    inti;
    for(i=0;i<size;i++){
        printf("a[%d]\n", i);
        printf("ID:"); scanf("%d", & a[i].id);
        printf("Name:"); scanf("%s", a[i].name);
    }
}

/* Display array a[ ] of length size */
void put_students (Student a[], int size)
{
    inti;

    printf("\nElement ID Name\n";
    for(i=0;i<size;i++){
        printf("a[%d]: %2d%-15s\n", i, a[i].id, a[i].name);
    }
}

int main (void)
{
    int size,horw,pos,key;
    char keystr [20];
    Student a [MAX_SIZE];

    printf("Number of data:"); scanf("%d", & size);
    get_students(a,size);
    printf("1)ID, 2)Name:");
    scanf("%d", &horw);

    switch(horw){
    case1:
        ssort_id(a,size); /* Sort by ID number in ascending order */
        put_students(a,size);
        printf("Search Key (ID):"); scanf("%d", & key);
        pos=bsearch_id(a,0,size-1,key);
        if(pos>=0){
            printf("Search key(ID)%d, name %s found in a[%d]\n", key, a[pos].name, pos);
        } else{
            printf("Search key(ID)%d not found\n", key);
        }
        break;
    case2:
        ssort_name(a,size); /* Sort by name in ascending order */
        put_students(a,size);
        printf("Search Key (Name):"); scanf("%s", keystr);
        pos = bsearch_name(a,0, size-1, keystr);
        if(pos>=0){
            printf("Search key (name)%s, ID %d found in a[%d]\n", keystr, a[pos].id, pos);
        } else{
            printf("Search key(name)%s not found\n", a[pos].name);
        }
        break;
    }

    return 0;
}