如何用一个字符替换两个字符？

Question

所以我试图在一个句子中用 & 替换 cc（例如："Hi this is Mark cc Alice"）。到目前为止，我有这段代码，它将第一个 c 替换为 & 但第二个 c 仍然存在。我将如何摆脱第二个 c?

int main() {
    char str[] = "Hi this is Mark cc Alice";
    int i = 0;
    while (str[i] != '[=10=]') {
        if (str[i] == 'c' && str[i + 1] == 'c') {
            str[i] = '&';  
            //str[i + 1] = ' ';
        }
        i++;
    }
    printf("\n-------------------------------------");
    printf("\nString After Replacing 'cc' by '&'");
    printf("\n-------------------------------------\n");
    printf("%s\n",str);
    return str;
}

输入为：

Hi this is Mark cc Alice

输出为：

Hi this is Mark &c Alice

Answer 1

您可以使用通用的“后移”功能将其随机播放到一个位置：

void shunt(char* dest, char* src) {
  while (*dest) {
    *dest = *src;
    ++dest;
    ++src;
  }
}

在哪里可以像这样使用它：

int main(){
  char str[] = "Hi this is Mark cc Alice";

  for (int i = 0; str[i]; ++i) {
    if (str[i] == 'c' && str[i+1] == 'c') {
      str[i]='&';

      shunt(&str[i+1], &str[i+2]);
    }
  }

  printf("\n-------------------------------------");
  printf("\nString After Replacing 'cc' by '&'");
  printf("\n-------------------------------------\n");
  printf("%s\n",str);

  // main() should return a valid int status code (0 = success)
  return 0;
}

注意从混乱的 int 声明 + while + 递增到一个 for 循环的切换。使用 char* 指针会更简洁：

for (char* s = str; *s; ++s) {
  if (s[0] == 'c' && s[1] == 'c'){
    *s = '&';

    shunt(&s[1], &s[2]);
  }
}

在使用 C 字符串时，重要的是要习惯使用指针，因为这可以为您省去很多的麻烦。

You should also familiarize yourself with the C Standard Library so you can use tools like strstr instead of writing your own equivalent of same. Here strstr(str, "cc") could have helped.

Answer 2

你必须将整个数组向左移动。一个简单的方法是：

#include <stdio.h>
#include <string.h>

#define STR_SIZE 25

int main(){
  char str[STR_SIZE] = "Hi this is Mark cc Alice";
  int i=0,j=0;

  while(str[i]!='[=10=]'){
    if(str[i]=='c' && str[i+1]=='c'){ 
      str[i]='&';
      for (j=i+1; j<STR_SIZE-1; j++) /* Shifting the array to the left */
      {
          str[j]=str[j+1];
      }
    }
    i++;
  }
  printf("\n-------------------------------------");
  printf("\nString After Replacing 'cc' by '&'");
  printf("\n-------------------------------------\n");
  printf("%s\n",str);
  return 0;
}

Answer 3

无需更改大部分代码，您也可以按照以下方式进行

#include <stdio.h>

int main()
{
  char str[] = "Hi this is Mark cc Alice";
  int i=0;
  while(str[i]!='[=10=]')
  {
    if(str[i]=='c' && str[i+1]=='c')
    {
      str[i]='&'; 
      // after replacing the first 'c' increment the i, so it will point to next c.
      i++;
      break;
      //str[i+1]=' ';
    }
    i++;
  }
  // replace previous char with next char until null
  while(str[i]!='[=10=]')
  {
      str[i] = str[i+1];
      i++;
  }
  printf("\n-------------------------------------");
  printf("\nString After Replacing 'cc' by '&'");
  printf("\n-------------------------------------\n");
  printf("%s\n",str);
  return 0;
}

Answer 4

可以使用二指法：使用单独的索引变量读写同一个数组中的字符。

#include <stdio.h>
#include <string.h>

int main() {
    char str[] = "Hi this is Mark cc Alice";
    int i = 0, j = 0;

    while (str[i] != '[=10=]') {
        if (str[i] == 'c' && str[i + 1] == 'c') {
            str[j++] = '&';
            i += 2;
        } else {
            str[j++] = str[i++];
        }
    }
    str[j] = '[=10=]';  // set the null terminator that was not copied.

    printf("\n-------------------------------------");
    printf("\nString After Replacing 'cc' by '&'");
    printf("\n-------------------------------------\n");
    printf("%s\n", str);
    return 0;
}

如何用一个字符替换两个字符？

How to replace two chars with one char?

c

loops

c-strings

char