現在ハッシュテーブルを使い、人物の検索をかければその人の年代が出てくるコードを書いています。下記の三つのソースコードをターミナルでgcc -c hash.c、gcc -c openaddr.c、gcc -c main.cとかけたところ、エラーが出てしまいました。なぜこのエラーメッセージが出てきしまうのかがわかりません。

エラーメッセージ

openaddr.c:30:14: warning: implicit declaration of function 'hash' is invalid in
      C99 [-Wimplicit-function-declaration]
    int hs = hash(id1);
             ^
openaddr.c:86:34: warning: more '%' conversions than data arguments [-Wformat]
                    printf("id: %s,  info: %d\n");}
                                ~^
openaddr.c:30:14: warning: implicit declaration of function 'hash' is invalid in
      C99 [-Wimplicit-function-declaration]
    int hs = hash(id1);
             ^
openaddr.c:86:34: warning: more '%' conversions than data arguments [-Wformat]
                    printf("id: %s,  info: %d\n");}
                                ~^
2 warnings generated.
main.c:9:5: warning: implicit declaration of function 'initialize' is invalid in
      C99 [-Wimplicit-function-declaration]
    initialize();
    ^
main.c:10:5: warning: implicit declaration of function 'enter' is invalid in C99
      [-Wimplicit-function-declaration]
    enter("Copernicus", 1473);
    ^
main.c:11:40: warning: implicit declaration of function 'hash' is invalid in C99
      [-Wimplicit-function-declaration]
    printf("enter Copernicus at %d\n", hash("Copernicus"));
                                       ^
main.c:22:5: warning: implicit declaration of function 'show_table' is invalid
      in C99 [-Wimplicit-function-declaration]
    show_table();
    ^
main.c:24:9: warning: implicit declaration of function 'search' is invalid in
      C99 [-Wimplicit-function-declaration]
    t = search(key);
        ^

ソースコード

#include <stdio.h>
#include <string.h>
#define M 257
#define NEXT_HASH(x) (x + 1) % M

int hash(char *v){
    int x=0;
    while (*v) x= 256*x + (*v++);
    if (x < 0) x = (-x);
    return (x % M);
}

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define M 257
#define NEXT_HASH(x) (x + 1) % M

struct item {
    char id[20];
    int info;
};

struct item table[M];

void initialize() {
    int i;

    for (i = 0; i < M; i++)
        memset(table[i].id, '\0', sizeof(table[i].id));
}

void show_table() {
    int i;
    for (i = 0; i < M; i++)
        if (strcmp(table[i].id, "") != 0)
            printf("[%3d] id: %20s,  info: %d\n", i, table[i].id, table[i].info);
}

int enter(char *id1, int info1) {
    int i;
    int hs = hash(id1);

    for (i = 0; i < M; i++) {
        if (!strcmp(table[hs].id, "")) {
            strcpy(table[hs].id, id1);
            table[hs].info = info1;
            return 0;
        }
        hs = NEXT_HASH(hs);
    }
    return -1;
}

int search(char *id1) {
    int hs = hash(id1);
    int next = hs;
    while(hs == hash(table[next].id)) {
        if (!strcmp(table[next].id, id1))
            return next;
        next = NEXT_HASH(next);
    }
    return -1;
}

int main(int argc, char *argv[]) {
    int qflag = 1;
    char str[20];
    int n, cmd;
    int cancel();
    int hashcode =search(str);

    while(qflag) {
        printf("1.. INSERT  2.. CANCEL  3.. SEARCH  4.. LIST  0..EXIT\n");
        scanf("%d", &cmd);

        switch(cmd) {
            case 1:
                printf("id   >> ");
                scanf("%s", str);
                printf("info >> ");
                scanf("%d", &n);
                enter(str, n);
                break;
            case 2:
                printf("id  >> ");
                scanf("%s", str);
                    //if(!strcmp(str, "%s"))
                    //memset(str, '0', sizeof(str));
                    //printf("%s canceled\n", str);
                break;
            case 3:

                printf("id  >> ");
                scanf("%s", str);
                if (hashcode ==0){
                    printf("%s fonded\n", str);
                    printf("id: %s,  info: %d\n");}
                else if (hashcode != 0){
                    printf("%s not found\n", str);}               
                break;
            case 4:
                show_table();
                break;
            case 0:
                qflag = 0;
                break;
        }
    }
    return 0;
}

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#define M 257

int main(){
    int t;
    char key[20];
    initialize();
    enter("Copernicus", 1473);
    printf("enter Copernicus at %d\n", hash("Copernicus"));
    enter("Galilei", 1564);
    printf("enter Galilei at %d\n",hash("Galilei"));
    enter("Newton", 1643);
    printf("enter Newton at %d\n",hash("Newton"));
    enter("Maxwell", 1831);
    printf("enter Maxwell at %d\n",hash("Maxwell"));
    enter("Einstein", 1879);
    printf("enter Einstein at %d\n",hash("Einstein"));
    enter("Heisenberg", 1901);
    printf("enter Heisenberg at %d\n",hash("Heisenberg"));
    show_table();
    strcpy(key, "Heisenberg");
    t = search(key);
    printf("%s => %d\n", key, t);

    return 0;
}