project x%10==0

#include<stdio.h>
#include<string.h>
struct cnct
{
    char name[1009];
    char mail[1009];
    char number_1[1009];
    char number_2[1009];
};

struct cnct a[1000];
int size;

void sort(int sz)
{
    int ipos=0,jpos=0;
    for(ipos=0; ipos<sz; ipos++)
    {
        for(jpos=ipos; jpos<sz; jpos++)
        {
            if(strcmp(a[ipos].name,a[jpos].name)>0)
            {
                struct cnct t=a[ipos];
                a[ipos]=a[jpos];
                a[jpos]=t;
            }
        }
    }
}

int main()
{
    FILE *inp;
    FILE *out;
    FILE *usr;
    inp=fopen("input.txt","r");
    usr=fopen("usr.txt","r");
    int n,i=0,j,command,sub,size=0;
    struct cnct usr_cnct;
    char x[1009];

    while(fscanf(inp,"%s",&a[i].name)!=EOF)
    {
        fscanf(inp,"%s",&a[i].mail);
        fscanf(inp,"%s",&a[i].number_1);
        fscanf(inp,"%s",&a[i].number_2);
        i++;
        size++;
    }
    sort(size);
    fclose(inp);
    while(1)
    {
        printf("Input Command\n1.Append\n2.Delete\n3.Display\n");
        //fgetchar();
        scanf("%d",&command);
        if(command==1 || command==2)
        {
            printf("Input\n1.From file\n2.From console\n");
            scanf("%d",&sub);
        }
        if(command==1)
        {
            if(sub==1)
            {
                fscanf(usr,"%s",&usr_cnct.name);
                fscanf(usr,"%s",&usr_cnct.mail);
                fscanf(usr,"%s",&usr_cnct.number_1);
                fscanf(usr,"%s",&usr_cnct.number_2);
            }
            else
            {
                scanf("%s",&usr_cnct.name);
                scanf("%s",&usr_cnct.mail);
                scanf("%s",&usr_cnct.number_1);
                scanf("%s",&usr_cnct.number_2);
            }
            int is=0,f_pos=size,c,qw;
            for(is=0; is<size; is++)
            {
                c=strcmp(a[is].name,usr_cnct.name);
                if(c>=0)
                {
                    f_pos=is;
                    break;
                }
            }
            if(strcmp(a[f_pos].name,usr_cnct.name)==0)
                a[f_pos]=usr_cnct;
            else
            {
                for(is=size-1; is>=f_pos; is--)
                    a[is+1]=a[is];
                a[f_pos]=usr_cnct;
                size++;
            }

            inp=fopen("input.txt","w");
            for(i=0; i<size; i++)
            {
                fprintf(inp,"%s\n",a[i].name);
                fprintf(inp,"%s\n",a[i].mail);
                fprintf(inp,"%s\n",a[i].number_1);
                fprintf(inp,"%s\n",a[i].number_2);
            }
            fclose(inp);
        }
        else if(command==2)
        {
            if(sub==1)
                fscanf(usr,"%s",&x);
            else
                scanf("%s",&x);
            int del_pos=-1,is,c;
            for(is=0; is<size; is++)
            {
                c=strcmp(a[is].name,x);
                if(c==0)
                {
                    del_pos=is;
                    break;
                }
            }
            if(del_pos!=-1)
            {
                for(is=del_pos; is<size; is++)
                    a[is]=a[is+1];
                size--;
            }
            inp=fopen("input.txt","w");
            for(i=0; i<size; i++)
            {
                fprintf(inp,"%s\n",a[i].name);
                fprintf(inp,"%s\n",a[i].mail);
                fprintf(inp,"%s\n",a[i].number_1);
                fprintf(inp,"%s\n",a[i].number_2);
            }
            fclose(inp);
        }
        else if(command==3)
        {
            for(i=0; i<size; i++)
            {
                printf("%s\n",a[i].name);
                printf("%s\n",a[i].mail);
                printf("%s\n",a[i].number_1);
                printf("%s\n\n",a[i].number_2);
            }
            printf("\n");
        }

        else
        {
            printf("Thanks\n");
            break;
        }
    }
}