用发write、fread将一张随意图片修改成德国国旗

#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#include<unistd.h>
int main(int argc, char *argv[])
{
	FILE* fp=fopen("./122.bmp","r");
	int w = 0,h = 0;
	fseek(fp,18,SEEK_SET);
	fread(&w,4,1,fp);
	fread(&h,4,1,fp);
	printf("图像尺寸为:%d * %d\n",w,h);
	fclose(fp);
	fp = fopen("./122.bmp","r+");
	fseek(fp,54,SEEK_SET);
	unsigned char yel[3] = {0,255,255};
	unsigned char red[3] = {0,0,255};
	unsigned char bla[3] = {0,0,0};
	for(int i=0;i<w;i++){
		for(int j=0;j<(h/3);j++){
			fwrite(yel,3,1,fp);
		}
	}
	for(int i=0;i<w;i++){
		for(int j=(h/3);j<(h*2/3);j++){
			fwrite(red,3,1,fp);
		}
	}
	for(int i=0;i<w;i++){
		for(int j=(h*2/3);j<h;j++){
			fwrite(bla,3,1,fp);
		}
	}
	fclose(fp);	
      return 0;
}

使用getch函数编写一个专门用来输入密码的函数，要求输入密码时显示*号输入回车，密码输入结束

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<unistd.h>
#include<termios.h>
#include<sys/types.h>
#include<assert.h>
int getch(){
    int c=0;
    struct termios org_opts, new_opts;
    int res=0;
    res=tcgetattr(STDIN_FILENO, &org_opts);
    assert(res==0);
 
    new_opts = org_opts;
 
    new_opts.c_lflag &= ~(ICANON | ECHO | ECHOE | ECHOK | ECHONL | ECHOPRT | ECHOKE | ICRNL);
    tcsetattr(STDIN_FILENO, TCSANOW, &new_opts);
 
    c=getchar();
 
    res=tcsetattr(STDIN_FILENO, TCSANOW, &org_opts);
    assert(res==0);
    return c;
}
void sec(char *sec,int len)
{
	int i=0;
	while(i<len-1){
		char c=getch();
		if(c==10){break;}
		printf("*");
		sec[i++]=c;
	}
	sec[i]='\0';
	printf("\n");
}
int main(int argc, char *argv[])
{
	char arr[10];
	sec(arr,10);

	printf("输入密码为:%s\n",sec);
      return 0;
}