16.8 计算平均年龄
#include <stdlib.h>
#include <stdio.h>
#define MAX_LEN 512 int main()
{
int age;
int totalAge;
float avgAge;
int peopleNum;
FILE *file;
char info[MAX_LEN];
char *infoPtr;
file = fopen("D:/family.txt", "r"); //按行读取文件
while(fgets(info, MAX_LEN, file)){
infoPtr = info;
peopleNum = 0;
totalAge = 0;
//strtol转换字符到数字
while((age = strtol(infoPtr, &infoPtr, 10)) > 0){
totalAge += age;
peopleNum++;
}
//类型转换为float,然后计算平均年龄
avgAge = (float)totalAge / peopleNum;
printf("%savg: %5.2f\n", info, avgAge);
} return 0;
}
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16.9 计算相同生日概率
#include <stdlib.h>
#include <stdio.h>
#include <time.h> //比较元素
int compare(void const *birth1, void const *birth2){
return *(int *)(birth1) - *(int*)(birth2);
} //打印数组
void print_arr(int *array, int len){
int idx = 0;
while(idx <= len){
printf("%d ", array[idx]);
idx++;
}
} //数组中是否有两个相同数
int count_same(int *array, int len){
int same = 0;
while(len > 0){
if(array[len] == array[len - 1]){
return 1;
}
len--;
}
return 0;
}
int main()
{
int times = 0;
int randBirthday[30];
int peopleCount;
int sameCount = 0;
srand((unsigned int)time(0)); while(times < 100000){
peopleCount = 29;
while(peopleCount >= 0){
randBirthday[peopleCount] = rand() % 365;
peopleCount--;
}
qsort(randBirthday, 30, sizeof(int), compare);
sameCount += count_same(randBirthday, 29);
times++;
}
printf("%f", (float)(sameCount) / 100000);
return 0;
}
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16.10 插入排序
#include <stdio.h>
#include <stdlib.h>
#include <string.h> //插入排序
void insert_sort(void *array, unsigned int length, unsigned int size, int (*handle)(void const *num1, void const *num2));
//整型移动函数 //整型比较函数
int int_compare(void const *num1, void const *num2)
{
return (*(int *)num1 - *(int *)(num2));
} //打印数组
void print_arr(int *arr , int len){
for(int idx = 0 ; idx < len; idx++){
printf("%d ", arr[idx]);
}
} int main()
{
int array[10] = {4, 1, 17, 2, 8 , 9, 22, 12, 7, 5};
insert_sort(array, 10, sizeof(int), int_compare);
print_arr(array, 10);
return 0;
} void insert_sort(void *array, size_t n_elements, size_t n_size, int (*handle)(void const *num1, void const *num2))
{
//存放临时需要位移的元素
char *temp = malloc(n_size);
//已排序的元素下标,从0开始，拿第二个元素和第一个对比
unsigned int sortIdx = 1;
//元素游标和已排序元素游标
unsigned int idx, idy;
//位移元素下面
unsigned int mov;
//从第二位开始，依次拿出元素和之前的已排序元素比较
for(idx = 1; idx < n_elements; idx++){
//开始比较
for(idy = 0; idy < sortIdx; idy++){
if(handle(array + idy * n_size, array + idx * n_size) > 0){
//将元素和已排序元素依次比较，当遇到已排序元素，比当前元素大时，当前元素应该插入到该已排序元素位置，已排序元素应该后移一位
//位移会覆盖后面的值，所以需要先保存需要插入的值
memcpy(temp, array + idx * n_size, n_size);
for(mov = sortIdx; mov > idy; mov--){
memmove(array + mov * n_size, array + (mov - 1) * n_size, n_size);
}
//元素插入
memcpy(array + idy * n_size , temp, n_size);
}
}
//如果需要插入的值，正好比已排序的值中最大的还要大，那么不需要移动，只要增加已排序的值得下标即可
sortIdx++;
}
}
运行：