Lec1-Brief Introduction

slides地址

Lec 1: Welcome

CS106L简介

与CS106B比较：

C++简介

这三个都是C++能编译通过的代码：

Ccde 1: 标准C++

#include <iostream>
int main() {
    std::cout << "Hello, world!" << std::endl;
return 0;
}

Code 2: 类C

#include "stdio.h"
#include "stdlib.h"
int main(int argc, char *argv) {
    printf("%s", "Hello, world!\n");
    // ^a C function!
return EXIT_SUCCESS;
}

Code 3: 汇编

#include "stdio.h"
#include "stdlib.h"
int main(int argc, char *argv) {
asm(  
"sub    $0x20,%rsp\n\t"             // assembly code!
"movabs $0x77202c6f6c6c6548,%rax\n\t"
"mov    %rax,(%rsp)\n\t"
"movl   $0x646c726f, 0x8(%rsp)\n\t"
"movw   $0x21, 0xc(%rsp)\n\t"
"movb   $0x0,0xd(%rsp)\n\t"
"leaq    (%rsp),%rax\n\t"
"mov    %rax,%rdi\n\t"
"call  __Z6myputsPc\n\t"
"add    $0x20, %rsp\n\t"
    );
return EXIT_SUCCESS;
}

C 的劣势：

• No objects or classes
• Difficult to write generic code
• Tedious when writing large programs

C++希望做到的（设计哲学）：

STL库的优越性：

• Tons of general functionality
• Built in classes like maps, sets, vectors
• Accessed through the namespace std::
• Extremely powerful and well-maintained