c语言实现大小端判断和二进制模式写入各种数据到文件

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#include <stdio.h>#include <stdlib.h>#include <inttypes.h>//测试大小端模式void test_endian(){    uint32_t i=0x04030201;    unsigned char* cp=(unsigned char*)&i;    if(*cp==1)        printf("little-endian\n");    else if(*cp==4)        printf("big-endian\n");    else        printf("who knows?\n");    //exit(0);}void write_int(){    int a=0x01001c00;//写入文件中变为00 1c 00 01,小端模式,从右往左    FILE* fp=fopen("int.bin","wb");    fwrite(&a,sizeof(a),1,fp);    fclose(fp);    printf("write_int ok!\n");}void write_int2(){    int a=1024;//小端模式，转换为16进制写入    FILE* fp=fopen("int1024.bin","wb");    fwrite(&a,sizeof(a),1,fp);    fclose(fp);    printf("write_int2 ok!\n");}void write_float(){    float a=1024.02;//小端模式,从右往左    FILE* fp=fopen("float.bin","wb");    fwrite(&a,sizeof(a),1,fp);    fclose(fp);    printf("write_float ok!\n");}void write_char(){    char a='m';//小端模式,从右往左    FILE* fp=fopen("char.bin","wb");    fwrite(&a,sizeof(a),1,fp);    fclose(fp);    printf("write_char ok!\n");}void write_string2(){    char *p;    FILE *fp;    char str[32]="example";    for(p=str;*p!=0;p++)        *p+=129;//将可见字符转换成不可见字符，不一定是加129    fp=fopen("string2.txt","w+") ;    fwrite(str,strlen(str),1,fp);    fclose(fp);    fp=fopen("string2.txt","r+") ;    fread(str,1,strlen(str),fp);    printf("%s\n",str);//在txt中显示的是乱码    for(p=str;*p!=0;p++) *p-=129;//转换成可见字符        printf("%s\n",str);    fclose(fp);}//fwrite(&a,strlen(a),1,fp);//以二进制形式对文件进行操作 不用使用fwrite了//以文本形式写入void write_string(){    char* a="yunshouhu";//小端模式,从右往左    FILE* fp=fopen("string.txt","w");    fprintf(fp,"%s",a);    fclose(fp);    printf("write_string ok!\n");}//以文本形式读取void read_string(){    char line[1024]={0};    FILE* fp=fopen("string.txt","r");    int len=fscanf(fp,"%s",&line);    fclose(fp);    printf("read_string=%s len=%d\n",line,len);}//默认8的倍数对齐 4+1+10=15=>16typedef struct Person{    int age;    char sex;    char city[10];} Person;//默认8的倍数对齐 16+4+10=30=>32typedef struct Student{    Person parent;//16    int weight;    char classroom[10];} Student;//默认8的倍数对齐 4+4+10=18=>24typedef struct Student2{    Person* parent;//存在指针到文件中的话，指针对应的数据会丢失，因为你只存储了他的地址，没有保存他的数据    int weight;    char classroom[10];} Student2;void write_struct(){    Person person;    person.age=26;    person.sex='m';    strcpy(person.city,"shenzhen");    FILE* fp=fopen("person.struct.bin","wb");    fwrite(&person,sizeof(person),1,fp);    fclose(fp);    printf("write_struct sizeof=%d ok!\n",sizeof(person));//16}void write_Student_struct(){    Person person;    person.age=26;    person.sex='m';    strcpy(person.city,"shenzhen");    Student stu;    stu.parent=person;//16    stu.weight=140;    memset(stu.classroom,0,sizeof(stu.classroom));//清零，否则是随机值    strcpy(stu.classroom,"204");    FILE* fp=fopen("student.struct.bin","wb");    fwrite(&stu,sizeof(stu),1,fp);    fclose(fp);    printf("write_Student_struct sizeof=%d ok!\n",sizeof(stu));//32}void write_Student2_struct(){    Person person;    person.age=26;    person.sex='m';    strcpy(person.city,"shenzhen");    Student2 stu;    stu.parent=&person;//16    stu.weight=140;    memset(stu.classroom,0,sizeof(stu.classroom));//清零，否则是随机值    strcpy(stu.classroom,"204");    FILE* fp=fopen("student2.struct.bin","wb");    fwrite(&stu,sizeof(stu),1,fp);    fclose(fp);    printf("write_Student2_struct sizeof=%d ok!\n",sizeof(stu));//24}//c语言实现大小端判断和二进制模式写入各种数据到文件。int main(void){    test_endian();    write_int();    write_int2();    write_float();    write_char();    write_string();    read_string();    write_struct();    write_Student_struct();    write_Student2_struct();    printf("write ok!\n");    return 0;}
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