C Program to Count Negative Numbers in an Array

• Write a C program to count all negative numbers of an array.

Required Knowledge

• C printf and scanf functions
• For loop in C
• Arrays in C

Algorithm to count negative numbers in an array
Let inputArray is an integer array having N elements.

• Using a for loop, traverse inputArray from index 0 to N-1.
• For every element inputArray[i], check whether it is negative number or not(inputArray[i] < 0) and increment the counter accordingly.

C program to count number of negative elements in an array

#include <stdio.h>
#include <conio.h>
  
int main(){
    int inputArray[100], elementCount, index, counter=0;
      
    printf("Enter Number of Elements in Array\n");
    scanf("%d", &elementCount);
    printf("Enter %d numbers \n", elementCount);
     
    /* Read array elements */
    for(index = 0; index < elementCount; index++){
        scanf("%d", &inputArray[index]);
    }
        
    /* Iterate form index 0 to elementCount-1 and 
 check for negative numbers */
    for(index = 0; index < elementCount; index++){
        if(inputArray[index] < 0) {
            counter++;
        }
    }
     
    printf("Number of Negative Elements in Array : %d\n", counter);
    getch();
    return 0;
}

Output

Enter Number of Elements in Array
8
Enter 8 numbers
2 -4 9 10 0 -5 -1 1
Number of Negative Elements in Array : 3