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This article mainly introduces the relevant knowledge of C language Iripple O flow design case analysis, the content is detailed and easy to understand, the operation is simple and quick, and has a certain reference value. I believe everyone will gain something after reading this C language Iripple O flow design case analysis article. Let's take a look at it.

Preface

Two functions, fscanf and fprintf, are used to read and write files, and there are more than two functions for reading files in C language. There are two ways to read the file in the article, the number of input lines and the use of EOF to judge the end of the file. % s does not need to use the address character & when reading, but is mainly used to enter an array of characters.

Environment: CodeBlocks text reading software: NotePadd++

I. title

Design of experimental I _ paw O flow

First, the purpose of the experiment:

Familiar with the use of file stream classes, master the operation of opening, reading, writing and closing files.

Second, the experiment time:

Third, the location of the experiment:

Fourth, the content of the experiment:

1. Enter the data of any number of students (student number, name, grade), store the data in the student.dat file, and then read all the data from the file and display it.

2. Program to connect the contents of two files into one file.

3. Write a program to add a line number to a text file and save it to another file.

5. experimental requirements: write all the source programs before getting on the computer

6. analysis of the experimental results:

Second, the code and effect [1]. The first question

Two file pointers are used, file1 and file2 pointers are used to write and read files, respectively, and both operate on student.dat files.

Student.dat files do not need to be created in advance

A structural array is used to store information about students' student numbers, names and grades.

When entering the number of students, use the number of students as the first line of the file for later reading

While entering each student information in the console, use the file1 pointer to save the current student data into the file

It should be noted that when saving a file, there is no automatic line wrapping, so you need to add a newline character at the end of the message.

Because you must ensure that the file already exists when reading the file, use the fopen function only after you close the file1 pointer

After that, the student's information is read and displayed according to the number of students in the first row.

# includestruct student {char number [20]; / / student number char name [20]; / / name int score;// score} stu [100]; / / student structure array int main () {FILE * file1 = fopen ("student.dat", "w"); / / file pointer, write FILE * file2;// file pointer, read int i; int num = 0 fopen / number of students printf ("number of students:") Scanf ("% d", & num); fprintf (file1, "% d", num); / / put the number of students on the first line of the file, for (int I = 0

< num;i++){//输入学生信息 printf("第%d位学生",i+1); printf("学号: "); scanf("%s", stu[i].number);//学号 printf("姓名: "); scanf("%s", stu[i].name);//姓名 printf("成绩: "); scanf("%d", &stu[i].score);//成绩 //存入文件 fprintf(file1,"%s %s %d",stu[i].number,stu[i].name,stu[i].score); } fclose(file1);//关闭文件指针 file2 = fopen("student.dat","r");//读取文件 fscanf(file2,"%d",&num);//读取第一行的学生个数 //printf("%d",num); for(int i = 0;i < num;i++){//显示文件的数据 //局部变量 char number[20]; char name[20]; int score; //获取当前行的数据 fscanf(file2,"%s",number); fscanf(file2,"%s",name); fscanf(file2,"%d",&score); //打印 printf("第%d位学生: %s %s %d",i+1,number,name,score); } fclose(file2); return 0;}[2]. 第二问

At the beginning, student1.dat and student2.dat must already exist, and student3.dat is a file generated by merging data that does not need to be created in advance.

First, the student1.dat file is read and stored in the structure array stu1

Then read the student2.dat file and store it in the structure array stu2

Save the number of lines to the first line of the student3.dat file

Then iterate through the stu1 and stu2 structure arrays and store the data.

# includestruct student {char number [20]; / / Student ID char name [20]; / / name int score;// score} stu1 [100], stu2 [100]; / / Student structure array int main () {int inum1Num2; char file_name1 [20]; char file_name2 [20]; char file_name3 [20]; FILE * file1,*file2,*file3 / / File pointer file1 = fopen ("student1.dat", "r"); / / read file 1 file2 = fopen ("student2.dat", "r"); / / read file 2 file3 = fopen ("student3.dat", "w"); / / write file 3 / / get file 1 content fscanf (file1, "% d", & num1); / / read the number of students on the first line for (int I = 0bot I < num1) Fscanf +) {fscanf (file1, "% s", stu1 [I] .number); fscanf (file1, "% s", stu1 [I] .name); fscanf (file1, "% d", & stu1 [I] .score); / / printf ("% d students:% s% d", stu1 [I] .number, stu1 [I] .name, stu1 [I] .score) } / get the contents of file 2 fscanf (file2, "% d", & num2); / / read the number of students in the first line for (int I = 0 file2 I < num2;i++) {fscanf (file2, "% s", stu2 [I] .number); fscanf (file2, "% s", stu2 [I] .name); fscanf (file2, "% d", & stu2 [I] .score) / / printf ("% d student:% s% s% d", int 1, stu2 [I] .number, stu2 [I] .name, stu2 [I] .score);} / / write file 3 fprintf (file3, "% d", num1+num2); for (stub I = 0% I < num1) Stu1 array fprintf (file3, "% s% s% d", stu1 [I] .number, stu1 [I] .name, stu1 [I] .score);} for (int I = 0 fprintf I < num1;i++) {/ / traversing stu2 array fprintf (file3, "% s% s% d", stu2 [I] .number, stu2 [I] .name, stu2 [I] .score) } / / printf ("student1.dat and student2.dat content stored in student3.dat"); printf ("copy succeeded!"); fclose (file1); fclose (file2); fclose (file3); return;} [3]. The third question

EOF is the sign of the end of the file, that is, End OF File. If the string you read is equal to EOF, it means that the end of the file has been read, and you can exit the traversal read operation.

The strcpy () function is used to copy the contents of the character array to another character array. The first parameter represents the target character array, and the second parameter needs to copy the original character array.

A dead loop is used to traverse the file and a local character array str is used to store the current line data

When the if statement is executed, two things are done: one is to store the current row data in the str array, and the other is to determine whether it is read to the end of the file

Prompt when the read is finished, and break out of a dead loop.

Otherwise, the str character array is copied to the str character array with the subscript num of the structure array t.

Then the subscript num is self-added, and then the traversal range of the structure array t is [0, num).

Traverses the structure array while writing to the file stu2.dat file.

Since the subscript starts at 0, the number of rows is equal to iSum 1.

# include#includestruct text {char str; / / character array, storing data for each line} t [100]; / / structure array int main () {FILE * file1 = fopen ("stu1.dat", "r"); / / file pointer, read FILE * file2 = fopen ("stu2.dat", "w"); / / file pointer, write int iMagnum = 0 / / read while (1) {/ / traverse the file stu1.dat char str [100]; if (fscanf (file1, "% s", str) = = EOF) {/ / if the last line is read, printf ("File read is over!"); break;} else {strcpy (t [num] .str, str) / / copy the character array to the structure array num++;// and locate it to the next structure}} / / write to the file for (int I = 0 politics I < num;i++) {/ / traverse the structure array t / / printf ("% s", t [I] .str); fprintf (file2, "% d% s", iTun1, t [I] .str);} fclose (file1) Fclose (file2); return 0;} this is the end of the article on "Design example Analysis of the C language Imax O flow". Thank you for reading! I believe you all have a certain understanding of the knowledge of "C language Ihammer O flow design case analysis". If you want to learn more knowledge, you are welcome to follow the industry information channel.

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