将gets（）字符串转换为C中的整数

Question

I am trying to write code that reads a string of numbers using gets() and then converts said string into an integer. However something is going wrong with my conversion and I can't figure out what. I also have to use gets() to do this. If anyone can see whats wrong or knows a better way to do this please help.

Thanks.

#include <stdio.h>
#include <math.h>
int main()
{
   char s[1000];
   int n = 0;
   printf("Input the number you wish to have converted\n");//asks the user to enter the number they want converted
   gets(s);//reads the input

   for (int i = 0; i < length; i++)
   {
      char temp = s[i] - '0';
      n = n + pow(10, length - i - 1) * temp;//converts from a character array to an integer for decimal to binary conversion
   }
}

Answer 1

Instead of using your own method to do this, there are a number of utilities in the standard library. Take a look at strol and sscanf . It's also wise to use fgets instead of gets as pointed out in the comments above.

Example

#include <stdio.h>
#include <stdlib.h>
int main()
{
    char s[1000];
    int n = 0;
    printf("Input the number you wish to have converted\n");//asks the user to enter the number they want converted
    fgets(s, sizeof(s), stdin);//reads the input

    n = (int)strol(s, NULL, 10);
    printf("Number from strol: %d\n", n);

    sscanf(s, "%d", &n);
    printf("Number from sscanf: %d\n", n);
}

You can even bypass fgets and use scanf if you don't want to keep the string:

#include <stdio.h>
int main()
{
    int n;
    scanf("%d", &n);
    printf("Number from scanf: %d\n", n);
}