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c - scanf not working as expected

I tried to execute the following simple code in ubuntu 15.10 But the code behaves odd than expected

#include<stdio.h>
int main(){
int n,i=0;
char val;
char a[20];

printf("
Enter the value : ");
scanf("%s",a);
printf("
Enter the value to be searched : ");
scanf("%c",&val);

int count=0;
for(i=0;i<20;i++){
 if(a[i]==val){
   printf("
%c found at location %d",val,i);
   count++;
 }
}
printf("
Total occurance of %c is %d",val,count);
   return 0;
}

output:
--------------------------
Enter the value : 12345678
Enter the value to be searched : 
Total occurance of is 0

The second scanf to get the value to be searched seems not to be working. The rest of the code executes after the first scanf without getting input second time.

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1 Answer

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by (71.8m points)

After first scanf(), in every scanf(), in formatting part, put a whitespace

So change this

scanf("%c",&val);

into this

scanf(" %c",&val);

Reason is, scanf() returns when it sees a newline, and when first scanf() runs, you type input and hit enter. scanf() consumes your input but not remaining newline, so, following scanf() consumes this remaining newline.

Putting a whitespace in formatting part makes that remaining newline consumed.


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