c字符串函数有哪些 C 字符串函数

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

  void string_length(); 

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

      string_length(); 

      return 0; 
  } 

  void string_length(){ 
      char str[20] = "Hello world"; 

      printf("str: %sn",str); 
      printf("length: %dn",(int)strlen(str)); 

  } 

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

  void string_explore(); 

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

      string_explore(); 

      return 0; 
  } 

  void string_explore(){ 
      char str[15] = "Hello world"; 
      int index; 

      for(index=0; index<strlen(str); index++){ 
          printf("%cn",str[index]); 
      } 

  } 

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

  void concatenating(); 

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

      concatenating(); 

      return 0; 
  } 

  void concatenating(){ 
      printf("====concatenating===n"); 

      char str1[30] = "hello"; 
      char str2[10] = "wolrd"; 

      strcat(str1,str2); 
      printf("result: %sn",str1); 

  } 

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

  void string_to_numeric(); 

  int main(int argc, const char* argv[]) { 
       
      string_to_numeric(); 

      return 0; 
  } 

  void string_to_numeric(){ 
      printf("====string_to_numeric===n"); 
      char str1[10] = "10"; 
      char str2[10] = "28.74"; 

      int num1; 
      float num2; 

      sscanf(str1,"%d",&num1); 
      sscanf(str2,"%f",&num2); 

      printf("num1: %dn",num1); 
      printf("num2: %fn",num2); 

  } 

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

  void numeric_to_string(); 

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

      numeric_to_string(); 
           
      return 0; 
  } 

  void numeric_to_string(){ 
      int n = 10; 
      float m = 23.78; 

      char num1[10]; 
      char num2[10]; 

      sprintf(num1,"%d",n); 
      sprintf(num2,"% .2f",m); 

      printf("num1: %sn",num1); 
      printf("num2: %sn",num2); 

  } 

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

  void string_parser(); 

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

      string_parser(); 

      return 0; 
  } 

  void string_parser(){ 
      char cities[40] = "Tokyo;Berlin;London;New York"; 
      char token[2]=";"; 
      char* city; 

      printf("cities: %sn",cities); 

      city = strtok(cities, token); 
      while(city  != NULL){ 
          printf("%sn", city ); 
          city = strtok(NULL, token); 
      } 

  } 

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

  void string_copy(); 

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

      string_copy(); 

      return 0; 
  } 

  void string_copy(){ 
      char str[15] = "Hello world"; 
      char new_str[20]; 

      strcpy(new_str,str); 
      printf("str: %sn",str); 
      printf("new_str: %sn",new_str); 

      memset(new_str,  "0", sizeof(new_str)); 
      strncpy(new_str,str,5); 
      printf("strncpy-new_str: %sn",new_str); 

  } 

#include <stdio.h> 
#include <stdlib.h> 
main()  
{ 
   char *str1 = "123.79"; 
   char *str2 = "55"; 
   float x; 
   int y; 
   printf("nString 1 is "%s"n", str1); 
   printf("String 2 is "%s"n", str2); 
   x = atof(str1); 
   y = atoi(str2); 
   printf("nString 1 converted to a float is %.2fn", x); 
   printf("String 2 converted to an integer is %dn", y); 
}  //end main  

#include <stdio.h> 
#include <string.h> 
main() 
{ 
   char *str1 = "A"; 
   char *str2 = "A"; 
   char *str3 = "!"; 
   printf("nstr1 = %sn", str1); 
   printf("nstr2 = %sn", str2); 
   printf("nstr3 = %sn", str3); 

   printf("nstrcmp(str1, str2) = %dn", strcmp(str1, str2)); 
   printf("nstrcmp(str1, str3) = %dn", strcmp(str1, str3)); 
   printf("nstrcmp(str3, str1) = %dn", strcmp(str3, str1)); 
   if ( strcmp(str1, str2) == 0 ) 
      printf("nLetter A is equal to letter An"); 
   if ( strcmp(str1, str3) > 0 ) 
      printf("Letter A is greater than character !n"); 
   if ( strcmp(str3, str1) < 0 ) 
      printf("Character ! is less than letter An"); 
}  // end main