c/c++处理命令行参数int argc char **argv的方法

第一种：switch

#include<iostream>#include<string>#include<cstring>#include<cmath>#include<complex>#include<algorithm>#include<vector>#include<utility>#include<cstddef> /*size_t*/#include<bitset>#include<assert.h>#include<cstdlib>//abort()#include<list>#include<map>#include<deque>#include<set>#include<iterator>#include<exception>#include<stack>#include<queue>#include<ctype.h>//atoi()using namespace std;void usage(){cout<<"usage"<<endl;}int main(int argc, char*argv[])/* Rong Tao .03.17 */{string version("");bool debug = false;for (int i=1;i<argc;i++){char *pchar = argv[i];switch(pchar[0]){case '-': {switch(pchar[1]){case'd':debug = true;break;case'v':version = string("gcc-4.8.5");break;case'h':usage();break;default:break;}}default: cout<<""<<endl;}}if(debug)cout<<version<<endl;return 0;}

第二种：unistd.h：getopt（参见：/cpp/u/hs12/）

#include <stdio.h>#include <unistd.h>int main(int argc, char **argv){int ch;opterr = 0;/*定义函数：int getopt(int argc, char * const argv[], const char * optstring);函数说明：getopt()用来分析命令行参数。1、参数argc 和argv 是由main()传递的参数个数和内容。2、参数optstring 则代表欲处理的选项字符串*/while((ch = getopt(argc, argv, "a:bcde")) != -1)switch(ch){case 'a':printf("option a:'%s'\n", optarg); break;case 'b':printf("option b:'%s'\n", optarg); break;default:printf("other option :%c\n", ch);}printf("optopt +%c\n", optopt);}