实验5 数组和指针

part1:实验方式1:

#include <stdio.h>
const int N=5;
int binarySearch(int x[], int n, int item);
int main() {
    int a[N]={1,3,9,16,21};
    int i,index, key;
    printf("数组a中的数据:\n"); for(i=0;i<N;i++)
        printf("%d ",a[i]);
    printf("\n");
    printf("输入待查找的数据项: ");
    scanf("%d", &key);
    index = binarySearch(a, N, key);
    if(index>=0)
        printf("%d在数组中，下标为%d\n", key, index);
    else
        printf("%d不在数组中\n", key); return 0;
}

int binarySearch(int x[], int n, int item) {
    int low, high, mid;
    low = 0;
    high = n-1;
    while(low <= high) {
        mid = (low+high)/2;
        if (item == x[mid])
            return mid;
        else if (item < x[mid])
            high = mid - 1;
        else
            low = mid + 1;
    }
    return -1;
}

 

实验方法2:

#include <stdio.h>
const int N=5;
int binarySearch(int *x, int n, int item);
int main() {
    int a[N]={1,3,9,16,21};
    int i,index, key;
    printf("数组a中的数据:\n"); for(i=0;i<N;i++)
        printf("%d ",a[i]);
    printf("\n");
    printf("输入待查找的数据项: "); scanf("%d", &key);
    index = binarySearch(a, N, key);
    if(index>=0)
        printf("%d在数组中，下标为%d\n", key, index);
    else
        printf("%d不在数组中\n", key); return 0;
}
int binarySearch(int *x, int n, int item) {
    int low, high, mid;
    low = 0;
    high = n-1;
    while(low <= high) {
        mid = (low+high)/2;
        if (item == *(x+mid))
            return mid;
        else if(item < *(x+mid)) high = mid - 1;
        else
            low = mid + 1;
    }
    return -1;
}

 

part2:1:

#include <stdio.h>
#include <string.h>
void selectSort(char str[][20], int n );
int main() {
char name[][20] = {"John", "Alex", "Joseph", "Candy", "Geoge"};
int i;
printf("输出初始名单:\n");
    for(i=0; i<5; i++)
printf("%s\n", name[i]);
selectSort(name, 5);
printf("按字典序输出名单:\n");
    for(i=0; i<5; i++)
printf("%s\n", name[i]);
return 0;
}
void selectSort(char str[][20], int n) {
    int i, j;
    char t[20];
    for(i=0; i<n-1; i++){
        for(j=0; j<n-1; j++){
        if(strcmp(str[i], str[j])<0){
            strcpy(t,str[j]);
            strcpy(str[j],str[j+1]);
            strcpy(str[j+1],t);
        }
        }
    }
}