c++输出格式控制_控制台程序的作用[通俗易懂]

int main(int argc, char** argv)
int main(int argc, char* argv[])

 main (int argc,char *argv[])

hello.exe data.txt //.txt也在.exe所在目录下

notepad.exe   example.txt   data.txt   train.txt 
 第一个参数　　　　第二个参数　　　第三个参数　　第四个参数
因此：argc = 4

int main(int argc, char* argv[])
{
    cout << "参数个数:" << argc << endl;
    cout << "参数内容：";
    for (int i = 0; i < argc; ++i)
    {
        cout << argv[i] << endl;
    }

    //std::cout << "Hello World!\n";
    system("pause");
}

#include <iostream>

int main(int argc, char **argv)
{
    while (argc-- > 0)
    {
        //printf("argv[%d]：%s\n", argc, argv[argc]);
        printf("argc:%d,*argv++：%s\n", argc,*argv++);
        //printf("argc:%d,*++argv：%s\n", *++argv);

    }
}

ProjectTest  Jack 中国 boin747 1.234  3.3333 8888 zhongguo
pause

//C/C++处理main（）函数命令行
#include <iostream>
#include <vector>
#include <string>
#include <ctype.h>//调用atoi函数
using namespace std;

const char* const prog_name = "prog";
const char* const prog_version = "version 1.0 (2011/8/24)";

//退出函数
inline void usage(int exit_value = 0){
    cerr<<prog_name<<"  usage!"<<endl;
    exit(exit_value);
}

int main(int argc,char* argv[]){
    //声明用于记录用户指定选项的变量
    bool debug_on = false;
    bool ofile_on = false;
    bool limit_on = false;

    string ofile_name;//记录出现的输出文件名
    int limit = -1;//限制值
    vector <string> file_names;//记录文件名

    cout<<"argc:"<<argc<<endl;
    for(int i = 1;i < argc; ++i){//读取argv中的每个选项
        //输出第i+1个参量
        cout<<"argv["<<i<<"]:"<<argv[i]<<endl;

        char *pchar = argv[i];
        switch(pchar[0]){//确定选项类型：-h,-d,-v,-l,-o;或者其他
            case '-':{
                cout<<"case \'-\' found"<<endl;
                switch(pchar[1]){//确定用户指定的选项：h,d,v,l,o
                    case 'd'://处理调试：
                        cout<<"-d found:debugging turned on!"<<endl;
                        debug_on = true;
                        break;
                    case 'v'://处理版本请求
                        cout<<"-v found:version info displayed!"<<endl;
                        cout<<prog_name<<":"<<prog_version<<endl;
                        return 0;
                    case 'h'://处理帮助
                        cout<<"-h found:help info!"<<endl;
                        usage();
                    case 'o'://处理输出文件
                        cout<<"-o found:output file!"<<endl;
                        ofile_on = true;
                        break;
                    case 'l'://处理限制量
                        cout<<"-l found:resorce limit!"<<endl;
                        limit_on = true;
                        break;
                    default://无法识别的选项
                        cerr<<prog_name<<":error:unrecognition option -:"<<pchar<<endl;
                        usage(-1);
                }
                break;
            }
            default://不以'-'开头，是文件名
                if(ofile_on){//输出文件名
                    cout<<"file name:"<<pchar<<endl;
                    ofile_name = pchar;
                    ofile_on = false;//复位
                }
                else if(limit_on){//限制值
                    limit_on = false;
                    limit = atoi(pchar);
                    if(limit<0){
                        cerr<<prog_name<<":error:negative value for limit!"<<endl;
                        usage(-2);
                    }
                }
                else{//文件名
                    file_names.push_back(pchar);
                }
                break;
        }
    }
    if(file_names.empty()){
        cerr<<prog_name<<":error:no file for processing!"<<endl;
        usage(3);
    }
    else{
        cout<<(file_names.size() == 1 ? "File":"Files")<<
            " to be processed are the followed:"<<endl;
        for(int i = 0;i < file_names.size();++i){
            cout<<file_names[i]<<"\t"<<endl;
        }
    }
    if(limit != -1){
        cout<<"user-specified limit:"<<limit<<endl;
    }
    if(!ofile_name.empty()){
        cout<<"user-specified ofile:"<<ofile_name<<endl;
    }
    
}