The essential C programming guide to becoming a systems programmer: Master the basics: Understand data types, operators, and control flow. Use functions and pointers: Functions break code into reusable chunks, and pointers allow direct access to memory. Perform memory management: effectively allocate and release memory to improve program efficiency. Practical application: Create a file I/O program to read the content from the input file and copy it to the output file.
C language is famous for its simplicity, efficiency and low-level access capabilities Well-known as the cornerstone on which operating systems, embedded systems, and other critical software are built. For those who wish to become systems programmers, proficiency in C is indispensable.
Requirements:
Write a C program to read a file from user input and convert it to The contents are copied to another file.
Code:
#include <stdio.h> #include <stdlib.h> int main() { // 声明文件指针 FILE *inputFile, *outputFile; // 打开输入文件 inputFile = fopen("input.txt", "r"); if (inputFile == NULL) { fprintf(stderr, "无法打开输入文件.\n"); exit(1); } // 打开输出文件 outputFile = fopen("output.txt", "w"); if (outputFile == NULL) { fprintf(stderr, "无法打开输出文件.\n"); exit(1); } // 从输入文件逐个字符地读取内容并复制到输出文件 char c; while ((c = fgetc(inputFile)) != EOF) { fputc(c, outputFile); } // 关闭文件 fclose(inputFile); fclose(outputFile); return 0; }
Description:
fopen()
function to open the input and Output file. fgetc()
function. fputc()
function. EOF
is a special constant that represents the end of the file. fclose()
function releases the resources associated with the file. Becoming proficient in C programming takes time and effort. By practicing the above concepts and building your own projects, you will gradually improve your skills and become a qualified systems programmer.
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