appending char to string in c

[Norgy]

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
 
int main() {
    char states [6][10]={"start","InNum","InID","Done","InASG","InCOM"};
    char state[] = "start";
    char Final[10] ;
    char temp[2] ;
    int n = 1;
    char ch,file_name[25];
    FILE *fp;
    fp = fopen("D:\\chech.txt","r");
 
    if( fp == NULL ) { 
        perror("Error while opening the file.\n");
        exit(EXIT_FAILURE);
    } 
 
    printf(state);
    while( ( ch = fgetc(fp) ) != EOF ){
 
//------------------------------------------------------------------------------------
//Start state
 
        if((ch=='0' || ch=='1' || ch=='2' || ch=='3' || ch=='4' || ch=='5' || ch=='6' || ch=='7' || ch=='8' || ch=='9')&&(state=="start"))
 
        {
            strcpy(state,states[1]);
 
            temp[ 0 ] = ch;
            temp[ 1 ] = '\0';
 
            strcat(Final,temp);
 
            printf(Final);
        }    
        }
 
    fclose(fp);
    printf("\r\n");
    return 0;
}

i am trying to take each character from a file and put it in a string and print this string
but when i write this code , it doesn't give any output

[weaknessforcats]

Part of your problem is here:

etc...|| ch=='8' || ch=='9')&&(state=="start"))

state is an array and "start" is another array.

By definition the name of an array is the address of element 0. Therefore, state is the address of state[0] and this address will always be different from the address of element 0 in "start".

Therefore, your "if" statement will always be false.

[Norgy]

still can't understand the problem
could you explain more please?

[weaknessforcats]

state=="start"

You can't compare strings this way. If you need to know whether two strings are equal then you use the strcmp library function:

strcmp(state, "start");

If this call returns a zero, then the strings are equal.

The == operator will check if two things are equal but in the case of arrays, it will just compare the addresses of the arrays rather than comparing the contents of the arrays. Comparing addresses will always be false since each array has its own address in memory.

[Norgy]

thanks a lot =)
i got it

[donbock]

By the way, you can replace

(ch=='0' || ch=='1' || ch=='2' || ch=='3' || ch=='4' || ch=='5' || ch=='6' || ch=='7' || ch=='8' || ch=='9')

with

isdigit(ch)

Look up the isdigit function to find out which standard header file you need to #include.

[Norgy]

yes, i have improved the code and put isdigit(ch) instead of 1,2,3,4,5,6,7,8,9
and included ctype.h in the header
thank you :)