Little Help Needed

The code is running well but I have two issues.
Firstly, from the 3rd printf command, when I input a character, it jumps to the next instruction without me clicking enter.

Secondly, I'm trying to store the string elements in a new char array and print the new array but I'm having complications.

Code:

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#include <stdio.h>#include <conio.h>
#include <math.h>
#include <stdlib.h>


int main (void)
{
        int N;
        printf("insert the length of string\n");
        scanf("%d", &N);


        char v, u, str[N];


        printf("insert the string element\n");
        scanf("%s", str);


        printf("insert a character from the element\n");
        v = _getch();
        printf("\n%c", v);


    printf("\n");


        printf("insert a character which you want to interchange with\n");
        u = _getch();
        printf("\n%c", u);


        printf("\n");


    int i;
        for (i=0;str[i]!='\0'; i++){
        if (str[i] == v){
            str[i] = u;
        }
        else
          continue;


        }


        printf("the values are:\n");
        puts(str);


        return 0;




}

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Quote:

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Firstly, from the 3rd printf command, when I input a character, it jumps to the next instruction without me clicking enter.

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Okay, do you realize that that is what getch() should do?

Also do you know that getch() is a non-standard function only available on certain compilers?

Perhaps you should consider either getchar(), or scanf() using the " %c" format specifier (note the leading space).

Hello Chibisco!

the next input with _getch() takes the character from the keyboard-buffer of the last input.
Co can delete this buffer with a simple function:

Code:

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void clearKeyboardBuffer(void)
 {
 while (getc(stdin) != '\n')
    ;
 }

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For other people which have no _getch() here is a example:

Code:

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// for LINUX Systems
#include <termios.h>
#include <unistd.h>
#include <fcntl.h> //for new version of kbhit
//#include <sys/time.h> old version

/// reads from keypress, doesn't echo
int _getch(){
    struct termios oldt, newt;
    int ch;
    tcgetattr( STDIN_FILENO, &oldt );
    newt = oldt;
    newt.c_lflag &= ~( ICANON | ECHO );
    tcsetattr( STDIN_FILENO, TCSANOW, &newt );
    ch = getchar();
    tcsetattr( STDIN_FILENO, TCSANOW, &oldt );
    return ch;
}
// End of Defintion for LINUX

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You can use this examples in your code like this:

Code:

---

#include <stdio.h>
#include <math.h>
#include <stdlib.h>
 
 // for LINUX Systems
#include <termios.h>
#include <unistd.h>
#include <fcntl.h> //for new version of kbhit
//#include <sys/time.h> old version

/// reads from keypress, doesn't echo
int _getch(){
    struct termios oldt, newt;
    int ch;
    tcgetattr( STDIN_FILENO, &oldt );
    newt = oldt;
    newt.c_lflag &= ~( ICANON | ECHO );
    tcsetattr( STDIN_FILENO, TCSANOW, &newt );
    ch = getchar();
    tcsetattr( STDIN_FILENO, TCSANOW, &oldt );
    return ch;
}
 
// End of Defintion for LINUX

void clearKeyboardBuffer(void)
 {
 while (getc(stdin) != '\n')
    ;
 }
 
 
 
int main (void)
{
    int N;
    printf("insert the length of string\n");
    scanf("%d", &N);
 
 
    char v, u, str[N];
 
 
    printf("insert the string element\n");
    scanf("%s", str);
 
    clearKeyboardBuffer();
 
    printf("insert a character from the element\n");
    v = _getch();
    printf("\n%c", v);
 
    printf("\n");
 
 
    printf("insert a character which you want to interchange with\n");
    u = _getch();
    printf("\n%c", u);
 
 
    printf("\n");
 
 
      for (int i = 0; str[i] != '\0';  i++){
        if (str[i] == v){
            str[i] = u;
        }
        else
          continue;
 
 
    }
 
 
    printf("the values are:\n");
    puts(str);
 
 
    return 0;
 
}

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By the way i think it could be a reason to declare the length of the array str[] by 'N':
the string what you read in in line 17 of your example is not limited.
That could be a reason.
Now my second example of your code:

Code:

---

#include <stdio.h>
#include <stdlib.h>
 
 // for LINUX Systems
#include <termios.h>
#include <unistd.h>
#include <fcntl.h>

/// reads from keypress, doesn't echo
int _getch(){
    struct termios oldt, newt;
    int ch;
    tcgetattr( STDIN_FILENO, &oldt );
    newt = oldt;
    newt.c_lflag &= ~( ICANON | ECHO );
    tcsetattr( STDIN_FILENO, TCSANOW, &newt );
    ch = getchar();
    tcsetattr( STDIN_FILENO, TCSANOW, &oldt );
    return ch;
}
 
// End of Defintion for LINUX

void clearKeyboardBuffer(void)
 {
 while (getc(stdin) != '\n')
    ;
 }
 
 
int main (void)
{
    //int N;
    //printf("insert the length of string\n");
    //scanf("%d", &N);
    //char v, u, str[N];
    //printf("insert the string element\n");
    //scanf("%s", str);
   
    char v, u, str[200];
   
    printf("insert the string element\n");
    /* scanf("%199s", str);  // limits the length to 199 elements*/
    scanf("%199[^\n]", str); // reads every character including space but not '\n' (=Enter)
 
    clearKeyboardBuffer();
 
    printf("insert a character from the element\n");
    v = _getch();
    printf("\n%c\n", v);
 
    printf("insert a character which you want to interchange with\n");
    u = _getch();
    printf("\n%c\n", u);
 
 
    for (int i = 0; str[i] != '\0';  i++){
        if (str[i] == v){
            str[i] = u;
        }
        else
          continue;
 
    }
 
    printf("the values are:\n%s\n", str);
    puts(str);
 
    return 0;
}

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