I am unable to copy characters from one string to another

Question

I am making a program that until the user type +, the typed string will be copied to another, for example stack+, or the copied string would only stack, I tried to make the code below only that did not work.

#include <stdio.h>

int main(int argc, char** argv)
{
  char nome[100], num1[100];
  int cont,i;
  scanf("%s", nome);
  cont = 0;
  for(i = 0; i < nome[i] != '+'; i++)
  {
     num1[cont] = nome[i];
  }
    num1[cont] = '\0';
    printf("%d\n", cont);
  return 0;
}

Answer 1

As already commented on the condition of for is not correct and should be:

nome[i] != '\0' && nome[i] !='+'

Which means, as long as I don’t get to the end and as long as I don’t get to one '+'.

In addition to the cont is not being incremented within the for. Actually that cont nor is it necessary and so I suggest that you remove it and keep only the i which is more than enough to solve the problem.

Rewrite to:

#include <stdio.h>

int main(int argc, char** argv) {
    char nome[100], num1[100];
    int i; //sem cont
    scanf("%s", nome);

    for(i = 0; nome[i] != '\0' && nome[i] !='+'; i++) {
        num1[i] = nome[i]; //utilizando so o i
    }
    num1[i] = '\0'; //com i aqui tambem
    printf("%s\n", num1);
    return 0;
}

See the code running on Ideone

I changed the last printf by one that shows the string copied to make it easier to view the result.

I think the idea of showing the cont at the end was to show until which letter was copied. In this solution the final value of i has the same information if you want to show it.

Answer 2

When you are walking the string just check that the character is equal to + and if it is you come out of the loop with a break;.

I saw that at the end you were displaying a counter that wasn’t even incremented, so it always displayed zero, I modified the printf to display the string until the first occurrence of +.

#include <stdio.h>

int main(int argc, char** argv)
{
  char nome[100], num1[100];
  int i;

  printf("Digite um texto ateh 100 caracteres:\n");
  scanf("%s", nome);

  for(i = 0; nome[i] != '\0'; i++){
    if(nome[i]!='+')
        num1[i] = nome[i];
    else
        break;

  }

  num1[i] = '\0';
  printf("Nova string: %s\n", num1);
  return 0;
}