In C, how to find the number of space within the input line by the user?

Question

I'd like to know how to detect the number of spaces within the line that is entered by the user? The scanf function that I am using is:

scanf (" %[^\n]s", &line[0])

Here line is my char variable.

Am I doing any mistake?

Answer 1

This is how you could count the spaces, given that you manage to successfully read the input:

uint spaces = 0;
size_t len = strlen(line);
for (size_t idx=0; idx<len; ++idx)
   if (line[idx] == ' ')
      ++spaces;

And BTW, take a look at these threads:

Max string length using scanf -> ANSI C

How to use sscanf correctly and safely

scanf is not your best buddy

Answer 2

int countspaces(const char *str)
{
  int count = 0 ;
  char c ;
  while((c = *str++) != 0)
  {
    if (c == ' ')
      count++ ;
  }

  return count ;
}

...
scanf (" %[^\n]s", &line[0])
int nbofspaces = countspaces(line) ;

Answer 3

Following program will print the number of spaces in a string.

    #include<stdio.h>
    void main(void)
    {
        char *input_string;
        unsigned int space_counter = 0;
        scanf("%[^\n]",input_string);
        while(input_string != '\0')
        {
           if(*input_string == ' ')//check whether the char is space
              space_counter++      //increment space counter

           input_string++;         //increment counter
        }
        printf("Number of spaces in the string=%d",space_counter);
    }