阵列(3)

19.5 用保留值标记阵列长度

保留值（这个值可以设定）：0，-1，

#include <stdio.h>
int maxv(int[]);

int main() {
    int a[4] = {1, 3, 4, -1}; // 这里的-1表示保留值
    printf("Max: %d
", maxv(a));
    int b[6] = {6, 9, 7, 8, 3, -1};
    printf("Max: %d
", maxv(b));
    return 0;
}

int maxv(int v[]) {
    int max = v[0], i = 1;
    while (v[i] != -1) {
        if (v[i] > max) {
            max = v[i];
        }
        i++;
    }
    return max;
}

Max: 4
Max: 9

Process returned 0 (0x0)   execution time : 12.892 s
Press any key to continue.

#include <stdio.h>
int length(int[]);

int main() {
    int v[] = {1, 2, 3, -1};
    printf("%d
", length(v));
    return 0;
}

int length(int v[]) {
    int i = 0;
    while (v[i] != -1) {
        i++;
    }
    return i; // 此时的i表示的是资料型别多少个，而数组长度为 i+1
}

3

Process returned 0 (0x0)   execution time : 4.187 s
Press any key to continue.