c - c 中的多功能实用程序问题。

Question

以下程序应该从命令行读取(使用argv[])并执行三个函数之一:

right(根据边长判断三角形是否为直角三角形:输入 mu -r [sidea] [sideb] [sidec]

findtext:(查找给定文件内的字符串序列:(即“hello”)并列出找到它的行号。

count:(计算制表符、单词和退格键的数量)。

Findtext.c 正在正常运行:

例如，如果我输入 ./mu -f [string] [file.txt]

它成功列出了文件以及找到该文件的文件中的行号。

但是当我使用 -r(right) 选项运行相同的代码时，它会出现以下段错误:

程序名称:./mu 3 段错误(核心转储)

这段代码哪里出错了？

#include <stdio.h>
#include <stdlib.h>
//#include "count.h"
//#include "right.h"
//#include "findtext.h"

#define STAND_ALONE 1
void right(int, char **);
void count(int, char **);
void findtext(int, char **);
#ifdef STAND_ALONE 
int main(int argc, char *argv[])
{

      printf("\n");
      printf("Can only use one option(-f, -c, -r) at once. sorry!\n");
      printf("\n");


         printf("Program name: %s\n", argv[0]);

    while ((argc > 1) && (argv[1][0] == '-'))
    {
        switch (argv[1][1])
        {
            case 'f': // findtext.c
                printf("%s\n",&argv[1][2]);
                findtext(argc, argv);
                                break;

            case 'r': // right.c
                printf("%s\n",&argv[1][2]);
                right(argc, argv);
                break;
                        case 'c': // count.c
                printf("%s\n",&argv[1][2]);
                count(argc,argv);
                break;

            default:
                printf("Wrong Argument: %s\n", argv[1]);

        }

        ++argv;
        --argc;
    }
    return (0);
}

#endif

void right(int argc, char *argv[]){
int a;
int b;
int c;
int largest;
int a2;
int b2;
int c2;

/*if(argc != 4){
printf("please enter 3 sides, only \n");
} */

a = atoi(argv[2]);
b = atoi(argv[3]);
c = atoi(argv[4]);
//printf("argv2:%s ",argv[2]);
if((a <= 0 )|| (b <= 0) || (c <= 0))
     printf("Only positive values allowed\n"); exit(0);

a2 = (a*a);
b2 = (b*b);
c2 = (c*c);


if((c > a) && (c > b))
     largest = c;
if((b > a) && (b > c))
     largest = b;
if((a > b) && (a > c))
     largest = a;



if(largest == a){
  printf("HEy hey hey!");
  if((b2 + c2) == a2){ printf("%s %s %s is a right triangle\n",argv[2],argv[3],argv[4]); } 
   else{printf("%s %s %s is not a right triangle\n",argv[3],argv[2],argv[4]);}
 }

if(largest == b){
   printf("HEy");
  if((a2 + c2) == b2){ printf("%s %s %s is a right triangle\n",argv[2],argv[3],argv[4]); } 
   else{printf("%s %s %s is not a right triangle\n",argv[2],argv[3],argv[4]);}

 }

if(largest == c){
  printf("yo");
   if((a2 + b2) == c2){ printf("%s %s %s is a right triangle\n",argv[2],argv[3],argv[4]); } 
   else{printf("%s %s %s is not a right triangle\n",argv[2],argv[3],argv[4]);}

 }




} /* end method right() */



void findtext(int argc, char *argv[]){
FILE *fin;
char buffer[100];
int counter;
char *ptr = buffer;
char *result;

//if(argc != 3) {printf("Usage: %s filename  argc:%d\n", argv[0], argc); exit(1);}
  fin = fopen(argv[3], "r");
  if(!fin) {printf("Unable to open %s\n", argv[2]); exit(1); }

 counter = 0; 
 while (fgets(buffer, 99, fin)){
   counter = counter + 1; 
   if(strstr(ptr,argv[2])){
      printf("%d. %s", counter, ptr);
      printf("\n");

     }

  }
  fclose (fin);


}


void count(int argc,  char **argv){
FILE *fin;

int lcounter = 0;
int count = 0;
char name[100];
char ch;

int word = 0;
int nchar = 0;



fin = fopen(argv[1],"r"); // open file

if(fin==0){

printf("Could not find specified file.\n");
exit(0);
}

while((ch = getc(fin)) != EOF)
{

  nchar++;
  if(ch == '\n')
    lcounter++;
  if(isspace(ch) || ch == '\t' || ch == '\n')
      word++;
}

printf("number of characters: %d\n",nchar);
printf("Lines: %d\n",lcounter);
printf("words: %d\n",word);
printf("\n");

fclose(fin);


}

Answer 1

if((a <= 0 )|| (b <= 0) || (c <= 0))
 printf("Only positive values allowed\n"); exit(0);

注意 if block 。您没有使用大括号。无论如何，在 right 函数的这一点上，程序将结束。

当然，这不是您要寻找的错误，但它提供了一个起点:错误必须在此点之前。

您可能需要调试此处发生的情况:

a = atoi(argv[2]);
b = atoi(argv[3]);
c = atoi(argv[4]);