C String manipulation functions

String for C-style (char p[n]; ）：

Length (strlen), append (strcat, strncat), compare (strcmp, strncmp), lookup (STRCHR , strstr) and so on.

-the version with N is a limited operation, not all. For example, strcmp compares two strings, while strncmp compares the first n characters of two strings.

--Append should use strncat, because strcat is in danger of overflow. (Oddly enough,strcat in my mingw32-gcc 4.9.3 here without prompting for errors.) ）

Input (scanf,gets,fgets,sscanf), Output (printf,puts,fputs ,sprintf).

-scanf also has the possibility of overflow, and will be blank (space, carriage return, etc.) as input termination.

-gets will only terminate the carriage return as input. But it also exists overflow possible.

--Thefgets is safe.

--sscanf is to read the contents of the string into the specified variable! The opposite of sprintf .

--sprintf is the output of a string of content to the specified strings!!

There is also a atoi function that converts a string to int . (atof--turn into floating point, others slightly)

--a should be the meaning of the char array.

Note: The above-mentioned overflow is a result of the length of the target character array that cannot accommodate the final result.

The code is as follows:

#include <stdio.h>#include<stdlib.h>#include<string.h>intMainintargcChar Const*argv[]) {    Chars1[ the]="Hello World"; Chars2[ the]="ABC defxxx"; strcat (s1, S2); //Append//strncat (S1, S2, strlen (S2));printf"%s\n", S1); intv = strcmp (s1, S2);//Compareprintf"%d\n", V); Chars3[]="Hello"; Chars4[]="Hello"; if(S3! = S4) {//the address should be compared.printf"%s! =%s\n", S3, S4); }    Chars5[]="helloaaa"; Chars6[]="hellobbb"; V= strncmp (S5, S6,5);//Comparison of the first 5 charactersprintf"%d\n", V);    strcpy (S5, S6); printf ("%s,%s\n", S5, S6); strncpy (S1, S2,3);//Copy the first fewprintf"%s,%s\n", S1, S2); inti = $; Charss[ -]={0}; sprintf (SS,"i =%d", i);//output The content you want to output to a string? printf"%s\n", SS); //Ss=itoa (i);//is not a standard C-language library function. VS has//Atoi is a standard C-language library function        Chars7[ -]="abc=500"; Chars8[ -]="5+6="; SSCANF (S7,"abc=%d", &i);//use the string as input to output the specified variable to the specified content. printf"%d\n", i); intb; SSCANF (S8,"%d+%d=", &a, &b); printf ("%d,%d\n", A, b); Const Char*p = STRCHR (S7,'=');//Find charactersprintf"%s\n", p); P= Strstr (S7,"b");//Find Stringprintf"%s\n", p); strcpy (S7,"abc_123_ee_xx"); P=strtok (S7,"_");//Replace _ to 0//printf ("%s,%p,%p\n", p, p, S7); //P=strtok (NULL, "_");//How do you know which is the right operation???? //printf ("%s,%p,%p\n", p, p, S7); //P=strtok (NULL, "_");//How do you know which is the right operation???? //printf ("%s,%p,%p\n", p, p, S7);     while(p) {printf ("%s,%p,%p\n", p, p, S7); P=strtok (NULL,"_"); }    return 0;}

C String manipulation functions