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cs:c_language:array_1

# Array (Example 1)

Concepts:
Arrays, initialization and utilization

Text:
Implement a C program that:

• after the declaration and the initialization of a vector of 10 elements
• finds and prints the first even number and its position in the array

Solution:

array_1.c
```/* Print the first even number and its position of a 10 elements array/vector. */

#include <stdio.h>
#define SIZE 10

int main(){

int vec[SIZE] = {1, 5, 3, 7, 10, 1, 2, 3, 4, 5};
int i;
int found = 0;

/* First solution */
for(i=0; i<SIZE && !found; i++){
if ( vec[i]%2 == 0 ){
found = 1;
}
}

/* Second solution */
i = 0; found = 0;
while ( i<SIZE && !found ){
if ( vec[i]%2==0 ){
found = 1;
}
i = i + 1;
}

if (found){
printf("EVEN NUMBER: %d (POSITION: %d)\n", vec[i-1], i-1);
} else {
printf("No even number is present in array\n");
}

return 0;
}```

The program:

• after the initialization of an array of dimension SIZE, directly performed during the declaration:
```  int vec[SIZE] = {1, 5, 3, 7, 10, 1, 2, 3, 4, 5};
```
• it scans the array by using a for cycle until all the elements of the vector are analyzed (condition i<SIZE) and until an even number is found (the variable found has a value different than 0, i.e., true). The variable found is set to 1 when the first even number is found in the vector.
```  for(i=0; i<SIZE && !found; i++){
if ( vec[i]%2 == 0 ){
found = 1;
}
}
```
• the same exercise can be resolved equivalently by using the while statement:
```  /* Second solution */
i = 0; found = 0;
while ( i<SIZE && !found ){
if ( vec[i]%2==0 ){
found = 1;
}
i = i + 1;
}
```
• results are printed at the end of the program. It is important to notice that at the exit of both the for and the while cycle, the variable i is the next position of the first even number. For such reason, to print the first even element of the vector and its position the variables vec[i-1] and i-1 must be used, respectivelly.
```  if (found){
printf("EVEN NUMBER: %d (POSITION: %d)\n", vec[i-1], i-1);
} else {
printf("No even number is present in array\n");
}
```