Read the data from file 'sortedcities.txt' containing names of their STD codes. Accept a name of city from user and use Binary Search algorithm to check whether the name is present in file and output the STD code, otherwise output 'city not in list'.

 Read the data  from file 'sortedcities.txt' containing names of their STD codes. Accept a name of city from user and use Binary Search algorithm to check whether the name is  present in file and output the STD code, otherwise output 'city not in list'.

//Reading from file

#include<stdio.h>

#include<string.h>

typedef struct city

{

    char name[20];

    int code;

} city;



//Fileread

int fileread(city a[20])

{

    FILE *fp;

    int i=0;



    fp=fopen("sortcities.txt","r");

    if(fp==NULL)

        printf("File Not Exist");

    else

    {

        while(!feof(fp))

        {

            fscanf(fp,"%s%d", a[i].name, &a[i].code);

            i++;

        }

        fclose(fp);

    }

    return i-1;

}



//Main

int main()

{

    int i, n,flag=0;

    char key[20];

    city a[20];

    n = fileread(a);



    for(int i=0; i<n; i++)

        printf("%s %d\n", a[i].name, a[i].code);



    binarysearch(0,n-1);

}



void binarysearch(int low,int high)

{

    int n;

    char key[20];

    city a[20];

    n=fileread(a);

    int mid;

    printf("\nEnter City: ");

    scanf("%s",&key);



    while(low<=high)

    {

        mid=(low+high)/2;

        if(strcmp(key,a[mid].name)==0)

        {



            printf("City Code: %d",a[mid].code);

            exit(0);

        }

        else if(strcmp(key,a[mid].name)>0)

        {

            high=high;

            low=mid+1;

        }

        else

        {

            low=low;

            high=mid-1;

        }

    }



    printf("City Not In List\n");

}

output:

Bangalore 80
Chennai 44
Delhi 11
Hyderabad 40
kolkata 23
Mumbai 22

Enter City: Delhi
City Code: 11
Process returned 0 (0x0)   execution time : 7.119 s
Press any key to continue.

sortedcities.txt file:

Bangalore 80
Chennai 44
Delhi 11
Hyderabad 40
kolkata 23
Mumbai 22