常见的C语言面试编程题

常见的C语言面试编程题(1) 求n的阶乘，这是一个比较简单的题目，有很多方法，但用递归方法是最简单的了:#include <stdlib.h> #include <stdio.h>int main(){long factorial(long n);long n;scanf("%ld",&n);printf("%ld",factorial(n));return 0;}long factorial(long d)//求阶乘{long m;if(d<0){printf("d的阶乘不存在!");}else if(d==0||d==1){m=1;}else{m=d*factorial(d-1);}return m;}(2)从一个文件读取整数，对其进行排序，然后再将排序的结果输入到原来文件当中，这是一个经常考的题目，即考你的文件操作，又考了排序，我在这里用的是选择排序#include <stdlib.h> #include <stdio.h>int readtoarray(int *a,FILE *fp)//从文件里将整数读到数组里 {int i=0;if(fp==NULL){exit(0);}while(fgetc(fp)!=EOF){fscanf(fp,"%d",&a[i]);printf("%d\n",a[i]);i++;}return i;}void writetofile(int a[],FILE *fp,int i)//将数组写到文件里去{int k = 0;if(fp==NULL){exit(0);}while(k<i){fprintf(fp,"%c%d",' ',a[k++]);}}void selectionSort(int *a,int i)//选择排序 {int m,n;int tmp,min;for(m=0;m <i-1;m++){min=m;for(n=m+1;n <i;n++){if(a[n]<a[min])min=n;}tmp=a[m];a[m]=a[min];a[min]=tmp;}}int main(){FILE* fp,* fpwrite;int i;int a[10];fp=fopen("2.txt","r");i=readtoarray(a,fp);fclose(fp);selectionSort(a,i);fpwrite=fopen("2.txt","w"); writetofile(a, fpwrite,i); fclose(fpwrite);return 0;}1，单向链表的插入，删除，逆序操作#include <stdio.h>#include <stdlib.h>typedef struct Node {int key;struct Node* next; }* node;node newNode(int k) {node n=(node)malloc(sizeof(node));n->key=k;n->next=NULL;return n;}void printlist(node n) {if(!n){printf("n is NULL list\n");}while(n){printf("%d",n->key);printf(" ");n=n->next;}printf("\n");}node newList(){int k;node head=(node)malloc(sizeof(node));;scanf("%d",&k);if(k==0){head=NULL;return head;}else{node n=newNode(k); head=n;while(k){scanf("%d",&k);if(k!=0){node n1=newNode(k); n->next=n1;n=n->next;}}n->next=NULL;return head;}}node insertNode(node n,int p,int k) {node n1=newNode(k);node head=(node)malloc(sizeof(node)); head=n;if(head==NULL){n1->next=head;return n1;}else{if(p==1){n1->next=head;head=n1;return head;}else{int i=2;while(i!=p&&(n->next)){n=n->next;i++;}if(n->next==NULL){printf("the p can't be found\n"); return head;}else{n1->next=n->next;n->next=n1;return head;}}}}node deleteNode(node n,int k){node n1=(node)malloc(sizeof(node)); node head=(node)malloc(sizeof(node)); head=n;if(head==NULL){printf("list is NULL\n");return head;}else{if(head->key==k){head=head->next;return head;}while(n->key!=k&&n->next){n1=n;n=n->next;}if(n==NULL){printf("can't find the same value as k in this list\n"); return head;}else{n1->next=n->next;n=NULL;return head;}}}node reverse(node n) {node n1[10];node head=(node)malloc(sizeof(node)); node n2=(node)malloc(sizeof(node)); head=n;if(head==NULL){return head;}else{int i=0;while(head!=NULL){n2=head;head=head->next;n2->next=NULL;n1[i]=n2;i++;}head=n1[i-1];for(int j=i-1;j>0;j--) {n1[j]->next=n1[j-1];}return head;}}int main(){node n=newList();printlist(n);//插入操作int k,p;scanf("%d,%d",&p,&k); node nn=insertNode(n,p,k); printlist(nn);//删除操作int q;scanf("%d",&q);node nd=deleteNode(nn,q); printlist(nd);//链表的倒置操作node m=reverse(n);printlist(m);return 0;}2，双向链表的插入删除操作#include <stdlib.h> #include <stdio.h> typedef struct Node {int key;struct Node* pre;struct Node* next;}* node;node newNode(int i) {node n=(node)malloc(sizeof(node));n->key=i;n->pre=NULL;n->next=NULL;return n;}node newduplinklist() {int i;scanf("%d",&i);node n;if(i==0){n=NULL;return n;}n=newNode(i);node head=n;int k=1;while(k!=0){scanf("%d",&k);if(k!=0){node n1=newNode(k);n->next=n1;n1->pre=n;n=n1;}}n->next=head;head->pre=n;return head;}int sizeduplinklist(node n) { if(n==NULL) return 0; node head=n;int i=1;while(head->next!=n){head=head->next;i++;}return i;}void print(node n) {if(n==NULL)printf("此时链表为空!");else{printf("输出链表:\n");for(int i=0;i<sizeduplinklist(n);i++) {printf("%-2d",n->key);n=n->next;}printf("\n");}}node insertNode(node n) {int p,k;printf("插入位置p:\n");scanf("%d,%d",&p,&k);printf("\n");if(p>sizeduplinklist(n)){printf("此位置超出链表的长度!\n"); return n;}else if(p<1){printf("此位置不存在!\n");return n;}else{node n1,head,m;m=newNode(k);head=n;if(p==1){m->pre=n->pre;n->pre->next=m;m->next=n;n->pre=m;return m;}else{int i=1;while(i!=p){n1=n;n=n->next;i++;}n1->next=m;m->pre=n1;m->next=n;n->pre=m;return head;}}}node delNode(node n) {int p;printf("删除位置p:\n"); scanf("%d",&p);printf("\n");if(p>sizeduplinklist(n)){printf("此位置超出链表的长度!\n"); return n;}else if(p<1){printf("此位置不存在!\n");return n;}else{node n1,head;if(p==1){ head=n->next;n->pre->next=n->next;n->next->pre=n->pre;return head;}else{head=n;int i=1;while(i!=p){n1=n;n=n->next;i++;}n1->next=n->next;n->next->pre=n1;return head;}}}int main(){node n=newduplinklist();printf("%d\n",sizeduplinklist(n));print(n);node m=insertNode(n); print(m);node m1=delNode(m); print(m1);return 0;}3，栈操作，用数组实现的包含出栈，入栈的操作#include <stdio.h> #include <stdlib.h> typedef struct Sta {int a[20];int num;}* sta;sta NullStack(){sta s=(sta)malloc(sizeof(sta)); s->num=0;return s;}sta pushstack(sta s,int i){s->a[s->num]=i;s->num=s->num+1;return s;}sta popstack(sta s) {if(s->num==0){printf("stack is NULL\n"); return s;}s->num=s->num-1;return s;}void printstack(sta s) {if(s->num==0){printf("stack is NULL\n");}else{for(int i=s->num-1; i>=0;i--){printf("%d\n",s->a[i]);}}}int main(){sta s=NullStack(); s=pushstack(s,1); s=pushstack(s,2); printstack(s); s=popstack(s);s=popstack(s);printstack(s);return 0;}4，队列操作，类似于栈，#include <stdio.h> #include <stdlib.h>typedef struct Que {int a[20];int num;}* que;que NullQueue() {que q=(que)malloc(sizeof(que)); q->num=0;return q;}que enq(que q,int i) {q->a[q->num]=i;q->num=q->num+1;return q;}que deq(que q){if(q->num==0){printf("queue is NULL\n"); return q;}for(int i=1;i<q->num;i++){q->a[i-1]=q->a[i];}q->num=q->num-1;return q;}void printqueue(que q) {if(q->num==0){printf("queue is NULL\n");}else{for(int i=q->num-1; i>=0;i--) {printf("%3d",q->a[i]);}}}int main(){que q=NullQueue(); q=enq(q,1); q=enq(q,2);q=enq(q,3);q=enq(q,4);printqueue(q);printf("\n");q=deq(q);//printf("%d",s->a[0]);//q=deq(q); printqueue(q); return 0;}。