Application of char in C language file operation

In C file operations, the char variable can be used to read a single character: through the fgetc() function. Write a single character: via the fputc() function. Read and write strings: through fgets() and fputs() functions. Perform other operations, including finding characters, locate file pointers, and judging file ends.

Application of char in C language file operations

In C, the char data type represents a single character. In file operations, char variables are widely used to read and write character data.

Read characters

 <code class="c">char ch; FILE *fp; // 打开文件fp = fopen("file.txt", "r"); if (fp == NULL) { // 文件打开失败处理} // 从文件读取单个字符while ((ch = fgetc(fp)) != EOF) { // 处理字符}</code>

Write characters

 <code class="c">char ch = 'a'; FILE *fp; // 打开文件fp = fopen("file.txt", "w"); if (fp == NULL) { // 文件打开失败处理} // 将单个字符写入文件fputc(ch, fp);</code>

Character array

Arrays of type char can be used to store multiple characters, so they can be used to read and write strings.

Read string

 <code class="c">char str[100]; FILE *fp; // 打开文件fp = fopen("file.txt", "r"); if (fp == NULL) { // 文件打开失败处理} // 从文件读取最多99 个字符到str 中fgets(str, 100, fp);</code>

Write string

 <code class="c">char str[] = "Hello, world!"; FILE *fp; // 打开文件fp = fopen("file.txt", "w"); if (fp == NULL) { // 文件打开失败处理} // 将字符串写入文件fputs(str, fp);</code>

Other applications

In addition to reading and writing character data, char can also be used in file operations to perform the following operations:

• Find characters: The fgetc() function can return the next character in the file, while ungetc() function can put characters back into the stream.
• Positioning file pointers: The fseek() function can locate file pointers to specific locations in the file.
• Determine the end of the file: the feof() function can check whether the file pointer has reached the end of the file.

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