C语言（复杂数据，DEVFORGE学编程社区）

1、小型数据库

#include <stdio.h> 
#include <stdlib.h>   
#define N 100

struct student{
    int no;
    char name[12];
    int score;    
}s[N];

int main()
{
    int n;
    scanf("%d",&n);
    /* 保存 */
    FILE *fp;    
    fp = fopen("DATA5614.DB","wb");    
    scanf("%d%s%d", &s[0].no,s[0].name,&s[0].score);
    fprintf(fp,"%d %s %d ", s[0].no,s[0].name,s[0].score);
    int max = s[0].score, index = 0;
    for(int i=1; i<n; ++i)
    {
        scanf("%d%s%d", &s[i].no,s[i].name,&s[i].score);
        fprintf(fp,"%d %s %d ", s[i].no,s[i].name,s[i].score);
        if(s[i].score>max){
            max = s[i].score;
            index = i;
        }            
    }        
    /* rewind */
    rewind(fp);
    /*读取 */
    fp = fopen("DATA5614.DB","rb");
    struct student stu;
    for(int i=0; i<=index; ++i)
    {
        fscanf(fp,"%d%s%d", &stu.no,stu.name,&stu.score);
    }
    printf("%d %s %d", stu.no,stu.name,stu.score);        
    fclose(fp);
    return 0;
}

2、检查图像文件格式

#include <stdio.h> 
#include <stdlib.h> 
#include <string.h>  

int main()
{
    char arr[100]="";
    char JFIF[]="JFIF"; //6
    char GIF89a[]="GIF89a";//0
    char PNG[]="PNG";//1
    
    FILE *fp;    
    fp = fopen("DATA5609.DAT","rb");    
    fread(arr,sizeof(unsigned char),100,fp);
    /*      */
    if(0 == strncmp(&arr[6],JFIF,4))
        printf("%s\n",JFIF);
    else if(0 == strncmp(&arr[0],GIF89a,6))
        printf("%s\n",GIF89a);
    else if(0 == strncmp(&arr[1],PNG,3))    
        printf("%s\n",PNG);
    else
        printf("NULL\n");
    fclose(fp);
    return 0;
}

3、重组字符串

#include<stdio.h>
#include <string.h>
#define N 100
void fun(char *s, char *t);
int main()
{
    char s[N] = "", t[N] = "";
    gets(s);
    fun(s,t);
    printf("%s",t);
    return 0;
}
void fun(char *s, char *t){
    int index = 0;
    for(int i=0; s[i]; ++i){
        if(i%2&&s[i]%2)
            t[index++] = s[i];            
    }
    t[index] = '\0';
}

4、分数加减法

#include<stdio.h>
#include <string.h>
#define N 100
void fun(int *num,int *den);
int main()
{
    char s[N] = "";
    gets(s);
    
    int a,b,c,d,num,den;
    a=s[2]-'0',b=s[0]-'0',c=s[4]-'0',d=s[6]-'0';
    if(s[3]=='+')num=b*d+c*a;    
    if(s[3]=='-')num=b*d-c*a;    
    den=a*d;
    if(!num) printf("0");
    else{
        fun(&num,&den);
        printf("%d/%d",num,den);
    }    
    return 0;
}
void fun(int *num,int *den){
    int t = *num>*den?*num:*den;
    while(t)
    {
        if((*num)%t==0&&(*den)%t==0){
            *num /= t;
            *den /= t;
            break;
        }
        t--;
    }
}

5、搜索字符

#include<stdio.h>
#include <string.h>
#define N 100
char* search(char *cpsource, char ch);
int main()
{
    char s[N] = "",ch;
    gets(s);
    ch = getchar();
    printf("%s",search(s,ch));
    return 0;
}
char* search(char *cpsource, char ch){
    int index=0, count=0, max=0;
    for(int i=0; cpsource[i]; ++i){
        if(cpsource[i]==ch){
            count++;
        }
        else{
            if(max<count){
                max = count;
                index = i-max;
            } 
            count=0;
        }
    }
    cpsource[index+max] = '\0';
    return &cpsource[index];
}

6、复数

#include<stdio.h>
#include <string.h>
#define N 100
typedef struct complex{
    double r;
    double i;
}COMPLEX;

int main()
{    /* 1 */
    COMPLEX c[2];
    double r,i;
    for(int i=0; i<2; ++i){
        scanf("%lf%lf",&c[i].r,&c[i].i);
    }
    /* 2 */
    char ch[5]="+-*/";
    for(int j=0; j<4; ++j){
        switch(ch[j]){
            case '+':
                r=c[0].r+c[1].r;
                i=c[0].i+c[1].i;
                break;
            case '-':
                r=c[0].r-c[1].r;
                i=c[0].i-c[1].i;
                break;
            case '*':   /* (ac-bd)+(bc+ad)i */
                r=c[0].r*c[1].r - c[0].i*c[1].i;
                i=c[0].i*c[1].r + c[0].r*c[1].i;
                break;
            case '/':   /*(ac+bd)/(c*c+d*d) +((bc-ad)/(c*c+d*d))i*/
                if(c[1].r||c[1].i){
                    r=(c[0].r*c[1].r + c[0].i*c[1].i)
                        /(c[1].r*c[1].r+c[1].i*c[1].i);
                    i=(c[0].i*c[1].r - c[0].r*c[1].i)
                        /(c[1].r*c[1].r+c[1].i*c[1].i);
                }
                else {
                    r=i=0;
                }                
                break;
        }        
        printf("(%.2f+%.2fi)%c(%.2f+%.2fi)=(%.2f%+.2fi)\n",
            c[0].r,c[0].i,ch[j],c[1].r,c[1].i,r,i);    
    }
    return 0;
}

7、插入字符

#include<stdio.h>
#include <string.h>
#define N 100

int main()
{    
    char s[N] = "", x;
    int i;
    gets(s);
    scanf(" %c%d",&x,&i);
    
    char t[N] = "";
    strncpy(t,s,i);
    t[i] = x;
    strcat(t,&s[i]);
    puts(t);
    return 0;
}

8、文件比较

#include <stdio.h> 
#include <stdlib.h> 
#include <string.h>  

int main()
{
    char str1[256]="";
    char str2[256]="";
    FILE *fp1,*fp2;    
    fp1 = fopen("DATA5613.TXT","r");
    fp2 = fopen("DATA5613.CPP","r");
    /*  */
    int i,j;
    for(i=0; !feof(fp1)&&!feof(fp2); ++i)
    {
        fgets(str1,sizeof(str1)-1,fp1);
        fgets(str2,sizeof(str2)-1,fp2);
        int flag = 0;
        for(j=0; str1[j]&&str2[j]; ++j)
        {
            if(str1[j]!=str2[j]){
                flag = 1;
                break;
            }                
        }
        if(flag)
            printf("%d %d\n",i+1,j+1);
    }
    /*  */
    fclose(fp1);
    fclose(fp2);
    return 0;
}

9、检测位图长宽

#include <stdio.h>
#include <stdlib.h>
#pragma pack(1)//结构体按1个字节对齐 3 
 typedef struct tagBITMAPFILEHEADER{//文件头 4 
    unsigned short bfType;//文件类型，固定为BM 5 
    unsigned int bfSize;//文件大小（字节） 6 
    unsigned short bfReserved1;//保留 7 
    unsigned short bfReserved2;//保留 8 
    unsigned int bfOffBits;//位图数据到文件头的偏移位置 9 
}BITMAPFILEHEADER; 

typedef struct tagBITMAPINFOHEADER{//位图信息头 11 
    unsigned int biSize;//位图信息头的长度 12 
    long biWidth;//位图的宽度，以像素为单位 13 
    long biHeight;//位图的高度，以像素为单位 14 
    unsigned short biPlanes;//位图的位面数 15 
    unsigned short biBitCount;//每个像素的位数
    unsigned int biCompression;//数据压缩类型 17 
    unsigned int biSizeImage;//位图数据大小（字节） 18 
    long biXPelsPerMeter;//水平分辨率（像素/米） 19 
    long biYPelsPerMeter;//垂直分辨率（像素/米） 20 
    unsigned int biClrUsed;//位图使用的颜色数 21 
    unsigned int biClrImportant;//调色板规范 22 
}BITMAPINFOHEADER;

int main()
{
    BITMAPFILEHEADER bmfh;
    BITMAPINFOHEADER bmih;
    FILE *bmp;
    //printf("%d,%d\n",sizeof(BITMAPFILEHEADER),sizeof(BITMAPINFOHEADER)); 
    bmp=fopen("DATA5611.BMP","rb");
    if(bmp!=NULL) {
        fread(&bmfh,sizeof(BITMAPFILEHEADER),1,bmp);
        fread(&bmih,sizeof(BITMAPINFOHEADER),1,bmp);
        //printf("位图宽=%d,高=%d\n",bmih.biWidth,bmih.biHeight);
        printf("%ld %ld\n",bmih.biHeight,bmih.biWidth);
        fclose(bmp);
    }
    return 0;
} 

10、POJer的烦恼

#include<stdio.h>
#include <string.h>
#define N 100

int main()
{    
    long long n;
    scanf("%lld",&n);
    int num[N] = {0},index = 0;
    while(n)
    {
        num[index++] = n%2;
        n /= 2;
    }
    
    for(int i=index-1; i>=0; --i)
        printf("%d",num[i]); 
    return 0;
}