经典C语言源代码1、(1)某年某月某日是星期几#include<stdio.h>int main(){int year, month, day;while (scanf_s("%d%d%d", &year, &month, &day) != EOF){if (month == 1 || month == 2)//判断month是否为1或2{year--;month += 12;}int c = year / 100;int y = year - c * 100;int week = (c / 4) - 2 * c + (y + y / 4) + (13 * (month + 1) / 5) + day - 1;while (week<0) { week += 7; }week %= 7;switch (week){case 1:printf("Monday\n"); break;case 2:printf("Tuesday\n"); break;case 3:printf("Wednesday\n"); break;case 4:printf("Thursday\n"); break;case 5:printf("Friday\n"); break;case 6:printf("Saturday\n"); break;case 0:printf("Sunday\n"); break;}}return 0;}1、(2)某年某月某日是第几天（一维数组）#include "stdio.h"void main() {int i, flag, year, month, day, dayth;int month_day[] = { 0,31,28,31,30,31,30,31,31,30,31,30,31 };printf("请输入年/月/日：\n");scanf_s("%d/%d/%d", &year, &month, &day);dayth = day;flag = (year % 400 == 0) || (year % 4 == 0 && year % 100 != 0);if (flag)month_day[2] = 29;for (i = 1; i < month; i++)dayth = dayth + month_day[i];printf("%d/%d/%d是第%d天\n", year, month, day, dayth); }2、30个数中找最小的数及其位置#include "stdio.h"# define SIZE 30void main() {int i;float data[SIZE];int min;printf("请输入%d个浮点数：\n",SIZE);for (i = 0; i < SIZE; i++) {//scanf_s("%f", &data[i]);data[i] = rand() % 30 + 1;printf("%f、", data[i]);}min = 0;for (i = 1; i < SIZE; i++) {if (data[i] < data[min])min = i;}printf("最小值是%5.2f,位置是%5d\n", data[min], min); }3、30个数从小到大排序（1）#include "stdio.h"# define SIZE 30void main() {int i,j;float data[SIZE],temp;int min;printf("请输入%d个整型数：\n",SIZE);for (i = 0; i < SIZE; i++) {scanf_s("%f", &data[i]);}for (i = 0; i < SIZE; i++) {min = i;for (j = i + 1; j < SIZE; j++)if (data[j] < data[min])min = j;temp = data[min];data[min] = data[i];data[i] = temp;}printf("\n排序后的结果是：\n");for (i = 0; i < SIZE; i++)printf("%5.2f", data[i]);}（2）模块化程序（数组名作为函数参数）#include "stdio.h"# define SIZE 5void accept_array(float a[], int size);void sort(float a[], int size);void show_array(float a[], int size);void main() {float score[SIZE];accept_array(score, SIZE);printf("排序前：");show_array(score, SIZE);sort(score, SIZE);printf("排序后：");show_array(score, SIZE);}void accept_array(float a[], int size) { int i;printf("请输入%d个分数：", size);for (i = 0; i < size; i++)scanf_s("%f", &a[i]);}void show_array(float a[], int size) { int i;for (i = 0; i < size; i++)printf(" %5.2f", a[i]);printf("\n");}void sort(float a[],int size) {int i, min, j;float temp;for (i = 0; i < SIZE; i++) {min = i;for (j = i + 1; j < SIZE; j++)if (a[j] < a[min])min = j;temp = a[min];a[min] = a[i];a[i] = temp;}}4、（1）指针加减：#include "stdio.h"#define SIZE 10void main() {int a[SIZE] = { 1,2,3,4,5,6,7,8,9,10 };int *pa, i;pa = &a[0];//pa=a;printf("\n");for (i = 0; i < SIZE; i++) {printf(" %d", *pa);//printf(" %d", *(pa+1));pa++;}}（2）指针比较：#include "stdio.h"#define SIZE 10void main() {int a[SIZE] = { 1,2,3,4,5,6,7,8,9,10 };int *pa, i;int *qa;pa = qa = &a[0];printf("请输入%d整型数：",SIZE);for (; pa < qa + SIZE; pa++)scanf_s("%d", pa);for (pa--; qa <= pa; pa--)printf(" %d", *pa);}5、两字符串相连：#include "stdio.h"#include "string.h"void str_cat(char str1[], char str2[]); void main() {int i, j;char str1[160];char str2[80];printf("请输入第一个字符串：");gets(str1);printf("请输入第二个字符串：");gets(str2);str_cat(str1, str2);puts(str1);}void str_cat(char str1[], char str2[]) { int i, j;i = 0;while (str1[i] != '\0')i++;j = 0;while (str2[j] != '\0') {str1[i] = str2[j];i++; j++;}str1[i] = '\0';}6、二维数组（a，b转置）#include "stdio.h"void main() {int i, j, b[2][3];int a[3][2] = { {1,2},{3,4},{5,6} };for (i = 0; i < 2; i++) {for (j = 0; j < 3; j++)b[i][j] = a[j][i];}printf("\na:\n");for (i = 0; i < 3; i++) {for (j = 0; j < 2; j++)printf("%5d", a[i][j]);printf("\n");}printf("\nb:\n");for(i = 0; i < 2; i++) {for (j = 0; j < 3; j++)printf("%5d", b[i][j]);printf("\n");}}7、输入一个二维数组并输出（指针）#include "stdio.h"void main() {int x[2][3];int i, j;for (i = 0; i < 2; i++)for (j = 0; j < 3; j++)scanf_s("%d", *(x + i) + j);putchar('\n');for (i = 0; i < 2; i++){for (j = 0; j < 3; j++)printf("%d ", *(*(x + i) + j));putchar('\n');}}8、冒泡法排序一个数组#include "stdio.h"#define size 10void maopao(int a[]);void main() {int a[10];int i;printf("请输入10个整数：\n");for (i = 0; i < 10; i++)scanf_s("%d", &a[i]);maopao(a);}void maopao(int a[]) {int i, j, temp;for (i = 0; i < 9; i++) {//进行9轮排序for (j = 0; j < 9 - i; j++)//每轮进行9-i次交换{if (a[j] > a[j + 1]){temp = a[j];a[j] = a[j + 1];//大的沉底，小的上浮a[j + 1] = temp;}}}printf("排序结果：\n");for (i = 0; i < 10; i++)printf("%4d", a[i]);}9、两数组A，B，要求A<B，如A：4，7，9B：1，3，5，8，9变换后A：1，3，5B：4，7，8，9，9#include <stdio.h>void ReArranger(int* A, int* B, int m, int n) //A和B是各有m个和n 个整数的非降序数组，本算法将B数组元素逐个插入到A中，使A中各元素均不大于B中各元素，且两数组仍保持非降序排列。