81 lines
1.6 KiB
C
81 lines
1.6 KiB
C
#include <stdio.h>
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#include <stdlib.h>
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#include <time.h>
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#include <math.h>
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#include <stdbool.h>
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// !指针应用场景
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/*
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1.函数返回多个值,某些值不方便直接返回,只能通过指针返回，传入的参数实际上是需要保存带回的结果的变量
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2.函数返回运算的状态，结果通过指针返回。常用的套路是让函数返回特殊的不属于有效范围内的 值来表示出错：-1或0（在文件操作会看到大量的例子）。当任何数值都是有效的可能结果时,就得分开返
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*/
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void swap(int *pa, int *pb);
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void minmax(int c[], int len, int *max, int *min);
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int divide(int a, int b, int *result);
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int main(void)
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{
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/* 1.交换两个变量的值 */
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int a = 5;
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int b = 6;
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swap(&a, &b);
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printf("a = %d, b = %d\n", a, b);
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/* 2.返回多个值*/
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int c[] = {1,2,3,4,5,6,7,8,9,12,13,14,16,17,21,23,55};
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int min, max;
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minmax(c, sizeof(c) / sizeof(c[0]), &max, &min);
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printf("max = %d, min = %d\n", max, min);
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/* 3.返回运算的状态 */
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int d=5;
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int e=6;
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int f;
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if (divide(d,e, &f))
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{
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printf("%d/%d = %d\n", d, e, f);
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}
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return 0;
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}
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void swap(int *pa, int *pb)
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{
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int t = *pa;
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*pa = *pb;
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*pb = t;
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}
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void minmax(int a[], int len, int *max, int *min)
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{
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int i;
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*max = *min = a[0];
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for (i = 1; i < len; i++)
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{
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if (a[i] < *min)
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{
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*min = a[i];
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}
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if (a[i] > *max)
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{
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*max = a[i];
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}
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}
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}
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int divide(int a, int b, int *result)
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{
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if (b==0)
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{
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return 0;
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}
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else
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{
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*result = a / b;
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}
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return 1;
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} |